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[RobbW]

So, I've been craving a solar filter for my C8-SGT lately. But, buying a ready-made filter at retail seems so expensive. I decided to make my own. I bought a sheet (roughly 8.5x11") of Baader AstroSolar film from Astro-Physics in Rockford. That stuff isn't cheap, but with the leftovers, I can make solar filters for my binos and probably one or two other scopes.

As far as the construction of a DIY filter, I really wasn't feeling like going through all the trouble of constructing one out of poster board or whatever. I looked over at my OTA and the dust cap on the end of it. Hmm..... why can't my dust cap pull double-duty?!?! So, I set about carefully measuring and cutting out a 2" offset hole in my dust cap. I then precisely taped a square of Baader film over the hole on the inside of the cap. I plan to fabricate some sort of velcro cover to put over the solar filter opening when not in use in order to protect the film.

I have not yet had a chance to deploy my new filter. However, at lunch today, I took a quick peek at the sun simply by holding the dust cap up in front of my eye. If that brief is any indication of how well this filter will work, I will be very happy. I will post additional notes after the filter's first light. In the meantime, I have linked an image to my redneck solar filter below.

Has anyone else attempted a DIY solar filter like this? Are there any negatives I should be concerned about by using my dust cap as the filter?

[Chicago Astronomer - Astro Joe]

Robb,

A caution.

Although the filter will block out a great deal of light from entering the tube, ( being that the light bounces around in there), there is a possibility of the heat build up as a factor. I have read where some SCT owners have cooked their innards doing solar work.

But, it's slight possibility.

The off-set opening is good not only for solar, but for full Moon viewing.

I think the Baader gives a bluish tint to the solar disk. There is another product that imparts a warmer orange glow.

But, you'll be ready for the Venus transit on June 6th 2012!

I think you'll be ok and I have been thinking about making up my own for years, but never got around to it.

[RobbW]

Joe, I tried out the solar filter very quickly today on my lunch break (very, very quickly). I didn't have time to take everything outside and do a proper setup. So I just set the scope up in my foyer looking out a window at the sun. First thing I realized.... it is damn difficult to find the sun with your telescope! You wouldn't think so with as big and bright as it is, but it is very hard. You can't use a finder scope or laser pointer to aim your scope. So you're basically having to go at it blind, so to speak. Anyway, I finally found my target. It was pretty neat. I didn't get a lot of time to study our star because I had to get back to work, and also because my daughter was begging for a look. And, of course, my wife took a peek as well.

I can't wait to get some quality time with this solar filter. I think it is a great idea to be able to do some type of astronomy day or night! In addition to the solar filter, I am also making preparations to do some live image broadcasting with my scope and a video camera. I already have a channel on Night Skies Network. I was just testing out the camera feed last night without the scope. Pretty neat! Now I'm Just waiting for the time to actually haul everything outside and get it set up and running. I'll keep you posted.

[Chicago Astronomer - Astro Joe]

Robb,

You are an encouragement.

I have had that Network just layin' in my favorites, doing nothin'. But perhaps will do something with it, eh?

Now that I can tether the Laptop to my Smartphone, I can be out in the field and do this kind of stuff.

Great that you are now a solar astronomer.

Next....H-Alpha scope?

When I open the Doane Observatory next time for solar viewing at the Adler, you and the other Chicago Astronomer must come down and peek thru the H-Alpha scope attached to the 20" Cassigrain.

(Also...what did you use to cut out the opening in the cover?)

[RobbW]

I used a 2" hole saw on my power drill and went very slowly. I have a question about the offset filter that will probably demonstrate my ignorance. Is one offset hole optimal for solar viewing? Or would there be any benefit to installing another hole on the opposite side of the cover? Or even four evenly spaced holes? I just have no idea what kind of problems or potential benefits doing something like that would bring about.

[Chicago Astronomer - Astro Joe]

Robb,

Interesting questions about multiple holes.

There is something called a "Hartmann Mask"...

www.undermidnight.com/articles/mask.htm

Used for focusing, but unsure how this would behave for solar.

I would try it out on cardboard and see what the results are.

Interesting experiment.

[patrickm]

I have NO experience with solar at all, but everything I've read counsels caution when using an SCT for solar. I think I'm gonna stick with my little refractor and save pennies for an H-alpha solar scope. Not too expensive at all on the bottom end.

So be careful. I'd hate to see you fry your new baby, and your wife hit you over the head with a dead scope!
p
-It's bleedin' demised!

[Chicago Astronomer - Astro Joe]

I must echo the caution again on the solar usage on your Cat.

I once did solar projection with my old trusty 4.5" reflector. Within about five minutes I could smell things were cooking inside the tube.

I stopped before anything warped and it was unfiltered - open tube toward the Sun, but still...light and heat are bouncing around inside the tube even with a filter.

I had the 60mm finderscope, (The one on the C11 now), attached to the 4.5" OTA at the time and switched over to it...and did the job well. A straight through job, (not including the diagonal), and safer.

Again, it's probably safe with that Baader filter, but I wouldn't.

Take this into consideration....

The Adler uses two scopes in the Doane Observatory for solar viewing...A larger H-Alpha scope and a 6" refractor with a white light aperture filter. Never used for solar viewing is the 20" Cassigrain main scope, which would probably deliver exceptional granulation and umbral detail...but the chances are just too great for heat build up and warpage.

(Hint on finding the Sun...use the shadow of the OTA on the ground/wall to find your target. When you get a perfect circle outline of the tube...you are close by... if not right on.)

[RobbW]

Thanks to you both for the warnings. To be honest, this is the first I had heard of any potential issues with using an SCT for solar. I had done a lot of searching and research on how to make a solar filter for an SCT, but never thought to question whether it should be done. I'm going to have to look into this more before putting it to full use.

[Paulie pchris00]

Robb, I also REALLY want a solar filter to view the sun, and a solar scope like Coronado would be great, but for now I've been happy with projection viewing. I found a cheap Orion refractor at a pawn shop awhile back for $30, but had no use for it... until I decided to turn it to the Sun. The projection thing is probably nowhere near as cool as a filter/solar scope, but it could be argued that our nigh sky targets aren't nearly as cool as the NASA APOD quality images we see regularly. But sunspots are easy enough to catch, and it's cool to check them against real time images.

Hillary and I even turned solar viewing into a sidewalk event two weeks ago, showing the Sun and last quarter Moon.






pchris00pnc.blogspot.com/2010/10/busy-week-of-september-26-october-1.html


It might be best to find a cheapie refractor for some initial viewing, something you won't be heartbroken over if it burns up.

I think it's funny that as a group we're getting that solar itch at the same time. Is it because the Sun is starting to wake up from it's longer than normal minimum cycle?

[Chicago Astronomer - Astro Joe]

Just in time for 2012.

[RobbW]

Yep, definitely got the itch for solar. Unfortunately, I don't know when I will have the time for viewing. It seems my time during the day is always completely booked. Have my daughter's soccer game and two birthday parties on Saturday. And Sunday, I'm supposed to be staining my in-laws' deck that I spent all last weekend stripping. And, of course, during the week, I work while the sun is out.

My big itch for solar viewing came about at the same time as my itch for video astronomy. I found the NightSkiesNetwork.com site a few weeks ago and have been hooked ever since. I love watching other astronomers' real-time imaging of their night skies. You can see so many more DSOs when you hook up a DSLR or video camera. I got so excited I decided to try it for myself. I Jimmy-rigged my Panasonic PV-GS150 to fit into my 2" diaganol and signed up for my own broadcast channel on NSN. I'm planning on tonight for first light with my video astronomy setup. We'll see how it goes.

As for the solar part of it, I was bummed that no one is ever broadcasting on NSN during the day when I'd like to take a break from my work responsibilities. I thought it would be cool to make a solar filter and offer something people can watch during the day on NSN

[Chicago Astronomer - Astro Joe]

Robb...

Call me when you start the broadcast and I'll follow along.

[RobbW]

Roger that, Joe! I really hope this works. The only concerns I have are the ability of my camera to absorb enough photons to see anything, and my wireless connection on my laptop being fast enough to stream the broadcast. I set up out in the far corner of my yard, and I can get a wireless signal, but it's usually not a very strong signal. So I will need to do some testing. Otherwise, I may just have to run out and buy 75' of CAT6 cable and wire this bad boy up.

[patrickm]

Robb, shoot me a text and I'll join from Austin. A beautiful night for a telescope here tonight. If only I had one...This will be almost as good!

[RobbW]

Well, I had the cam hooked up to my scope last night and had a decent (not great) view of Jupiter streaming. I was just about to call Joe and post a notice on the site about my broadcast when my scope suddenly started acting wacky. My GoTo had a hiccup while trying to slew to a new target. So had to stop broadcasting to realign. Then I lost my GoTo altogether. Then something got bumped and my tracking was suddenly completely off. All in all, it was a very disappointing first attempt. I will try again when I get another free night. Next time, I won't begin my broadcast until I'm sure everything is working just right. Last night was embarrassing! Sorry for the no-show guys.

[patrickm]

Lol. Sorry amigo. That sounds like one of my nights! If you read any of my observation session posts, you know it's true. That certainly sucks, but I've been there.

A great sage from Indiana once said, "Sometimes it's just like that," or something close to it. An exceedingly polite northern Indiana way of saying, "Sh1te happens," I think.

I do feel your frustration though, but lessons learned I guess.

My night? Why I'm glad you asked. I say this not to solarthreadjack, but to offer solace in shared frustration...

Watched from Austin as the household favorite Rangers blew a five run lead and 98% chance to win in one inning without getting even one out. I hate the Yankees as much as Paulie hates the Cubs, and only take small solace in a ball going between the legs of HGHRod.

Than got Mom to bed, but even with sleep meds she woke up twice confused about what home and town she was in and where we had been traveling to, though she hasn't left her house in a week.

The third time she got up, around two, I pulled out heavy artillery and made warm milk and we watched most of the Saturn episode of "The Universe" on DVD. What a weird planet! If we could find a big enough bath tub, thing would float! And it has a huge, perfectly hexagonal hole sitting on the top of it! You are a strange bird, mighty Saturno.

Finally got Mom off to bed again and decided to see if I could spot 103P/Hartley in my 15x70 binos. Spent a few minutes with the heart-stopping Orion Nebula high in the Eastern sky, and then turned my attention to Perseus and Hartley 2. I start identifying Capella and the guide stars in Perseus, but it suddenly gets really difficult. Even Capella is not popping in the eyepieces. WTF is going on?! After about ten minutes struggling with this, I finally give, remove my eyes from the back, and see a layer of low clouds has rolled in unannounced and unpredicted by CSC or anybody else!! WTF! Really? I glance at Orion and Jupiter and they are mere smudges. It's all over but the whining...

So there ya go! I'm not saying mine's better or worse, just that stuff does definitely happen. Even Joe doesn't have perfect nights! We can curse ourselves and the skies, or pack up, have a glass of wine, figure our lessons, vent, and go to bed. (This does not always work for me!)

Have never seen that website, and am a little afraid to go there, but you will get it all figured out, maybe tonight, and it will be cool when you do!

Now about that solar filter...

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[Chicago Astronomer - Astro Joe]

Considering Steve, Robb and I all had malfunctions...

...perhaps Astro Gremlins are about.

[patrickm]

Oct 16, 2010 12:49:49 GMT -6 Chicago Astronomer - Astro Joe said:

Considering Steve, Robb and I all had malfunctions...

...perhaps Astro Gremlins are about.

I did order a reticle eyepiece this week, but was in no danger of actually using it. Perhaps AstroGodz are quantum and don't recognize distance as a mitigating factor?

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[RobbW]

Damn it, Patrick! It was YOU again!!! Just kidding, of course. One bit of solace I got out of the whole evening came at about 1:30am when I finally started to pack it in. My GoTo and tracking were shot, so there was no sense in trying to video anymore. Just before disconnecting everything, I decided to throw an EP back on the scope and manually guide it to Orion. It was finally a good ways up above the horizon and the first opportunity I have ever had to view it in a scope. I aimed at the belt and had a good look at the three main stars. Then, looking at Orion naked eye, I saw this tiny cluster of stars below and to the right of the belt. Wondering what that was, I slewed my scope in the general area. With my eye to the EP, I slowly searched in that area until suddenly this ghostly patch of bright, wispy nebula came into view. Orion's Nebula! I had never seen it in real life before. It was beautiful. And so cool to actually see one of these DSOs that you read about, see pictures of, and watch Discovery programs on. It was really neat!

I'm thinking I may possibly go out for another try at some video astronomy tonight. Lord knows I need the practice. I don't know if I will broadcast or not after last night's debacle. However, I did learn some valuable lessons. We'll see.

[patrickm]

The Great Nebula is the second thing, after Saturn, that I saw that made me stop breathing when I saw it. It was the first thing that made Julia finally stop and say, "Wow. OK. That is pretty cool." Spoiled by too many Hubble photos, and even then, it transcends unrealistic expectations.

The volume of light from it is so huge that, like Saturn, it looks completely fake. I can't say that seeing it in a 114mm scope is any less awesome than the Hubble fly through pics. Just different.

Glad you took the time to find it. I tried the other night even with a dewed over scope but it wasn't over the top of the tree line. Another few weeks and we'll have it for months. Will be hard to target anything else.

Anxious to throw a filter on it!

[RobbW]

Yes, it WAS pretty amazing to see! I only wish I didn't have to wait until 1:30am to actually see it. I would love to bring my wife out to have a peek. I'm sure even she would think it's cool. However, there's no chance in my dragging her out that late. And, unfortunately, by the time it rises early enough in the evening for her liking, there's no way I'll be able to drag her out in 12 degree weather!

As for my solar filter, I'm really anxious to actually put it to use. Unfortunately, after spending the entire last weekend stripping my in-laws' deck, I have to spend all day today staining it. However, I'm hoping that if I get an early enough start and with the help of my Wagner Power Sprayer, I'll be able to knock this puppy out in no time. The actual act of staining won't take very long. It's preparing everything before hand. I have to mask off all the siding and everything else to prevent overspray getting on anything other than the deck.

Anyway, if I get done early enough, I'm going to see if I can get a little bit of time for solar filter first light. We'll see!

[RobbW]

Okay, so I have a question. How does one polar align your mount during the day when you cannot see Polaris? If I want to set my scope up to track with the sun, how would I accomplish that?

Also, I took heed of your warnings about using an SCT for solar observing. Not wanting to destroy my recent acquisition, I did more research specifically about solar viewing with an SCT. What I have found has calmed my nerves quite a bit and I now feel comfortable with proceeding. While caution is still advised, here is what I have found. The Baader Astro film I used to construct my filter blocks 99.999% of the sun's light. I am not using a full-aperture filter but a mere 2" offset filter. I will be using the filter for direct viewing rather than projection. This means the sunlight will be filtered before it even enters the optical path. I think most of the warnings regarding solar viewing with an SCT are geared towards those wanting to attempt projection viewing. Since the sun light travels the length of the OTA three times before hitting the EP and is concentrated each time, things can heat up very, very quickly and cause irreparable harm to your OTA. However, since I will be blocking 99.999% of the light prior to it entering the OTA and using a relatively tiny aperture, I am fairly confident my scope should be safe.

[patrickm]

Daytime Polar Alignment
Haven't tried it, but looks simple enough. Basically a more precise method of what Joe was suggesting just to find the sun in the first place.

Also remember to go into the GoTo software and set tracking for Solar.

Can you hook up to the internet? If so, plz text me so I can check it out.

Good luck!

[Chicago Astronomer - Astro Joe]

I have rarely needed to track the Sun, other than public demonstrations or special events like the Mercury/Venus transits. Sometimes I don't even align anything - having the axis of the scope pointing any which way...nudging it as needed.

I usually use the Mighty Nikon refractor at the Adler for solar projection, which is all manual, but when on an extended public sessions, I align to various points along the area to keep just handling just the one axis slo-mo cable.

Using the Adler's dead camera on dome and pavement squares for constant cardinal references, I align the scope's axis to familiar points - ..and thru several sessions have discovered my ground marks for good tracking and quick set-up.

[RobbW]

No go. Unfortunately, the sun was already below the tree line by the time I got home from stain the deck. Oh well. It just makes the anticipation that much greater for when I finally get a chance to peek at our sun. Maybe next weekend.

[patrickm]

Interesting post on Solar Alignment from Cloudy Nights. Dig it.

[Chicago Astronomer - Astro Joe]

Looking at the Sun will make you blind.

Sometimes the Sun dances around like the chicks saw at Fatima.

[Paulie pchris00]

Robb, I have seen the Night Sky Network once, and thought it was cool enough. I'd been wanting to do something similar, which is how a Facebook friend in California alerted me to NSN, but I don't have the capability for it. I was thinking more like doing a video of me doing a lunar observation, or getting video at a sidewalk session, something I could edit and post to youtube later. I'm curious to see what you can do on NSN.

let me in the loop when you're ready to go live, and I'll try to watch.