Post by Chicago Astronomer - Astro Joe on Jul 10, 2010 3:35:20 GMT -6
Two Chicago Astronomers...no waiting...
Mini Session
09 July 2010
Mini Session
09 July 2010
This evening was reserved for going up north...to the Dearborn Observatory with the Chicago Astronomical Society crew, since the area around the Adler Planetarium was locked down for a concert nearby - changing the plans for their monthly meeting. It was very cool of them to invite the Chicago Astronomers to join in, but, near the end of the day...I did not have my heart in traveling up to Evanston and decided to stay home.
Some members and fans of the Chicago Astronomer offered to provide me with a much needed lift and although really appreciated the offers....I was not ready for a long drive.
Later on in the afternoon, Chicago Astronomer Bill rang me and encouraged me to get out and take advantage of a clear night.
Ok.
We load his jeep up with the C11 and related equipment and off we go to Chicago Astronomer site #2. But...there was that damned concert we had to contend with by Northerly Island. Stopping at the Check-points, we were let through, (after all...we are Chicago Astronomers....
), and in no time.....we were at our spot by 10:30 pm and ready to go.This session was a test for two items.
One, putting the Bahtinov Focusing Mask I made,
( astronomer.proboards.com/index.cgi?board=ATM&action=display&thread=2775 )
...thru it's preliminary test...
and two - testing out the exaggerated dew shield I am making.
- First, the mask.
I did not take any pics of the mask usage in this session, but it works great. Aiming the C11 toward Altair, the diffraction spikes appeared just like others have experienced - and when centered...perfect focus.
Sweet!
I dig it and will be a regular part of my arsenal.
- Next...the Elongated Dew Shield or (E.D.S).....
A full narrative is forth coming on this Dew Shield project, but I wanted to see if it worked now. It's not finished, as I need to sew some Velcro and make some adjustments, but for this session...good ole duct tape to the rescue.
(Duct tape....God's gift to mankind...
)The primary purpose for the shield, of course, is to slow down the dew formation on the corrector plate, but I also wanted to make the light path into the tube...as dark as possible, blocking out the intrusive street lighting from hitting the corrector plate.
It is very dark in there. Very dark & deep....sweet!
Details on the dew shield later in another post. But it stuck out nearly 28 inches from the edge of the OTA and looks like a cannon!
Something William Herschel would have built!
I need to cut it down some, but does it do the job....?
Let's see.
Bill, our master DSO finder went straight to work...
On an easy target, we locate M13 in Hercules. Good contrast and individual stars easily observed. It took magnification quite well, but it seems that the quality of the skies were degrading and I have seen M13 brighter and clearer before.
Next, another easy target M57...and it's bright and big, kicking up the mag to a 17mm and using a Narrowband Nebula filter, it popped right out in a nice display. Bill liked the Skyglow filter on it, but Broadband and OIII did little to bring out detail.
With filters at the ready, we slewed over to the Dumbbell Nebula, M27. A ghostly image with it's familiar shape, it's a pretty big object - filling the 32mm eyepiece. But throwing in a Narrowband filter brought it out nicely. And again, Bill liked the Skyglow filter. Both did a nice job in increasing contrast and "brightening" the object.
At 11:30 pm, we tried the "Veil Nebula" NGC 6960, but were unsuccessful in visualizing it with all this damned light pollution.
Shooting over to M56, a globular cluster in the constellation Lyra - it was a straight line from M57 and through Alberio. At Magnitude 8, I could still discern individual stars. The best views were with a 17mm and even with a 10mm, but it became too dim to study. A bright star close by made it easier for Bill to locate it. I'm referring to it as "The Forgotten Cluster".
(How he finds all these is remarkable!)
I have started taking down logs of the sessions, to better remember what we saw and transcribe here on the Chicago Astronomer. Using a red light pen that fellow Chicago Astronomer Steve gave me, writing in darkened locales is a snap.
While targets were being found, I was goofing with the Raw Power Chinese Laser...
I dig it.
Next M71.
A globular cluster in Sagitta, it had a wide spread in a 32mm and took a 25mm well. A triangle of brighter stars near by made this 8 Magnitude cluster easier to make out individual stars. Nice.
It was close to 1:00am now, and surprise....Jupiter had risen. It's earlier and earlier rise surprises me...
Even in this 15 second 12X zoom exposure, one can make out a Jovian satellite trail.
Cassiopeia and Andromeda were nicely displayed before us and we took a peak at M31. A nice bright fuzzball. I think about things.....Without photography, the astro forefathers would have kept mistaking this object as a nebula...I think.
Side note: I broke Bill's chair...
An arm just snapped.
Sigh.
I will replace it, but still....damn...
Next, we go to M22, an elliptical globular cluster in the constellation Sagittarius, it looked good in a 25mm and individual stars could be resolved easy.
We also attempted to resolve the "Lagoon Nebula" - M8, but could not observe it. Completely washed out by sky ambiance, but we did get to view NGC 6530, a open cluster in extreme close proximity. Good wide spread and bright, but no Lagoon behind it...
We viewed Jupiter, now that it was higher, and still...no SEB. But, while observing Jupiter, we noticed that there was some Chromatic Aberration around the planet. SCT's are not supposed to have this artifact. Could it be the right angled prism? Removing it, I view the planet again - straight through...
But still, the same.
This needs some thinking to solve.
But, by 1:30 am, we pack up, shut down the session and break down the site.
It was a good session under the stars.
Some observations......
- The extended dew shield helped to increase contrast very nicely, keeping stray light out and a straight light path to the stars. I will continue finishing it this weekend and make it shorter...into attachable parts. As a test, we observed the Andromeda galaxy - first with the Elongated Dew Shield (EDS), and then without. The contrast was better with - and the galaxy brighter.
- The Bahtinov Focusing Mask is a great tool to have - especially for astroimaging. No regrets in making it, saving me $30.00! Yay!
- We saw some new targets this session, but the sky conditions deteriorated and at the end, a lot of haze. Even the Mag flashlight I use cast a visible beam.
-
The mount tracked nicely, but I needed to move the OTA farther back on the dovetail rail to balance it - considering that cannon tube I put on in the front. I also need to add a weight to the weight shaft.
- And...I needed to get out and this session was a cool one...
