Posts Made By: Bob Chester

Some clouds but none in the way.
My first try at shooting an eclipse.
Coolpix 4500
TV 32mm plossl
Tak FS78 w/5.9 reducer on CG4

14 seconds at F2.6 ISO 400

Can't wait to see what some of you pros post.
Bob

Position of best focus varies with each individuals eyes. I've always told eyeglass wearing guests at my telescope that if they don't suffer from astigmatism to remove thier glasses and refocus with great success.
My question is: How does this effect afocal photography or systems that use a 'calibrated' eyepiece to find focus for ccd chips etc.? It seems to me that a person would need perfect vision to use a 'calibrated' eyepiece.
The reason I ask is: my digital camera seems to have great difficulty focusing at the eyepiece in auto-focus mode and I seem to have the best luck locking it to infinity and then refocusing the scope. Is it possible that my eyes focus somewhere the camera just isn't capable of focusing on?

Yeh, it's cloudy here. Bob

Added bonus question: Do eyeglass wearers, using manually focused cameras, take out-of-focus pictures when not wearing glasses?

Hello all,
Can anyone tell me at what rpm the RA motor turns while tracking with the Losmandy drive system or the Celestron 492 drive? I'm thinking of replacing my 1/2 rpm Hurst AC motors with a DC stepper system and hope the Losmandy drive would be a simple solution.
Bob

6" f6.5 newt.
B&L 26mm Plossl
Coolpix 4500
3 images stacked and processed as B&W in Registax 2

Clear skies to all, Bob

I'm searching for opinions from some of the optical experts out there.
I have a nice little 6" newt and for years have had a 1.3" secondary in it. This sec. is pyrex and was advertised as 1/10th wave (no documentation) and the scope has always star tested very good, if not excellent.
About 1-1/2 years ago I purchased a 1.52" sec. for better illumination when using 35mm film. It is one of those expensive 1/20th wave quartz sec. that come with full test documentation. It has been in the scope since I got it but dispite all my efforts has never star tested as well as the 1.3". I usually attributed the poor star test to seeing conditions and the fact that the primary needed recoating. I had the primary recoated and still the star test did not improve.
Tuesday night I reinstalled the 1.3" pyrex and even while tweaking the collimation I could tell the star test was going to be much improved. After the scope acclimated I did a star test and the results were a definate improvement.
I surely do not want to accuse anyone of falsely claiming the precision of thier secondaries so these 2 questions arise.

1. Would an oversized secondary further illuminate surface errors in the primary resulting in an apparently poorer star test?

2. Since I did extensive bare mirror star testing with the 1.3" while I was figuring the primary have I created a matched optical set that may not star test well with a different secondary? Note-- the bare mirror did not pass the star test untill the Foucault numbers were dead on so I sort of doubt this one.

Your opinions please.

Bob

p.s. I use Novak supports so no adhesives or stress is applied to the secondaries. Stress was my first thought but has been eliminated as a cause.

A parasite infested stray I found in a parking lot. He's clean, fixed and fat now.
Bob

Between the foul weather and moonlit nights. I've yet to shoot a full 36 exposure roll of film this summer. I'm lucky to get 3 or 4 (20 to 45 min.) exposures a night.

How do you folks fill a whole roll and or store your camera between shoots?
Bob

My daughter has decided she wants to see dad. So, she is flying me from Minneapolis to Seattle for an eight day visit. Kids can turn out O.K..
Among the priorities on my to-do list is to visit ATWB. There are NO telescope stores in Minnesota. Some camera stores carry a very limited assortment but no Taks or T.Vs to be seen.
I wish I could say I was bringing a wheelbarrow full of money but economics don't allow. There are a couple small items I hope they have in stock though.
Herb, I promise not to drool on the displays......Well, I'll bring paper towels.

Loking foward to the visit,
Bob

For those thinking of painting a tube. I got a flier in the mail from these folks today. They have some pretty cool paints and additives.

No, I have no affiliations with them.
This would be a nice look for a solar scope.


http://www.alsacorp.com/index.htm

Bob

The moon was still low in the sky but these shots came out OK.

This is a shot of Mare Imbrium, Copernicus and the Apennines.

6" f6.5 newt
CP4500

Bob