Quote:

---

Actually the advertised load capacity of the mount is 40 pounds and my main and guide scopes plus mini-dovetail and tube rings weighs 38 pounds. So that's two pounds below the advertised weight (not including counter weights).

---

Post Extras:

Quote:

---

An observatory would be nice if I have the time and space to build one.

I have a Celestron focal reducer. Right now the only place I can mount it is right at the rear cell of C-11. But I have to have about 3" - 4" extension to the camera because the diameter of Orion StarShoot camera is so big that it hits the JMI Motofocus without the extension. I think the extension is causing excessive vignetting. I have not yet figured out how to place the FR at the camera or in between the camera and extension. I am sure I can but I have not been looking hard enough.

Actually the advertised load capacity of the mount is 40 pounds and my main and guide scopes plus mini-dovetail and tube rings weighs 38 pounds. So that's two pounds below the advertised weight (not including counter weights).

Peter

---

I missed the part about your camera being obstructed by the focuser in your earlier post. Gotta' do something about that. Bobby had a good suggestion, but, as always, costs astrobucks to do it.

It's my understanding that a said focal reducer has an optimum distance between the chip or film plane and the reducer. I don't know what the Celestron's is, but I'm sure someone here will be able to tell you.

Seems like a lot of problems can be solved with more astrobucks.

David

Post Extras:

Quote:

---

Uncle Rod,

Yes, I am imaging at F/10. I already tried f/6.3 focal reducer but I get huge vignetting probably because I have to use about 4" extension in order to prevent from the camera to hit the JMI Motofocus. The diameter of StarShoot Pro CCD camera is huge. The reducer was connected to the rear cell first, then 4" extension and then the camera. I can't yet figured out how to mount the reducer between the 4" extension and the camera. Will it work better if the reducer is mounted right in front of the camera?

Peter

EDIT: Please define "East heavy". Does it mean when counter weight shaft is at horizontal and pointing east and counter weight end is heavier than the scopes?

---

Yep. However, the best setup, the proper spacing, is still reducer, prime focus adapter, camera (I don't like to use them dadgummed 1.25-inch nosepieces; way too much change o' somethin' slippin). If I had to choose between a moto-focus thing-a-my-bobby and the 6.3 I'd dern shore choose the 6.3. Tryin' to get well guided images at f/10 with a C11 is NOT for the faint of heart.

East heavy means that with the scope on the east side of the mount the OTA wants to sink slightly to the east. With the scope on the west side, the counterweights want to sink slightly to the east. The idea is that you want the drive gears to PULL THE SCOPE ALONG.

Post Extras:

Quote:

---

This was my original target before I started having problems. Later that night I imaged M1 as shown earlier in this thread.

NGC891
C-11 at F/10, 2800mm F/L
2 frames of 15 minutes each
1 frame of 10 minutes

Imagine what this would look like if I had image it all night with 15 minutes (or longer) each frame!!!! If I only knew exactly the issue I am having.

Peter

---

Post Extras:

Quote:

---

I saw this in Cats & Casses thread about a pretty cool Off Axis Guider:

http://www.taurus-tech.com/tracker.htm

I read several reviews via Google and it received pretty high marks. I have read many people hates OAG but this is a really cool gadget.

OAG could eliminate the need to use guide scope mounted on main scope and save weight and possible greatly reducing flexure.

Peter

---

I would strongly suggest you go the drift alignment/reducer-corrector route first and see if that works for you. Believe you me, using an OAG is NOT fun. Any OAG. Who invented the things, Church Lady? "Hmmm....let's see...could it maybe...be...SATAN?!"

Post Extras:

Quote:

---

Not to be argumentative but I just want to bring back the mirror flop issue. My friend that just dealt with the problem showed me image progressions as he imaged from ~45 degrees up to the meridian and his stars got progressively worse and peaked as he approached the meridian. Theoretically, I think it makes more sense that the mirror slowly shifts position rather than getting to the meridian and then completely/suddenly shifting all at once. As a side note, all his imaging is with a 6.3 reducer.

I know some other more experienced people here have stated that your problem probably isn't mirror flop and considering that my experience is more 2nd hand I'll defer to them but I think when all else fails you can't completely rule mirror flop out.

---

Post Extras:

Quote:

---

Uncle Rod,

Thanks for the suggestions.

I thought if the object I want to image is dim, I need to increase the exposure for each frame. I also thought stacking more frames simply increases signal to noise ratio, not necessarily make the object brighter. That's why I thought I needed to expose NGC891 a little longer for each frame. I can't even see NGC891 with my naked eye using eyepieces. Probably because of some light pollution from casinos in Reno. I had to expose about 100 seconds just to barely see if my Atlas GOTO mount found it and it did! It was almost dead center. Then it took me about 10 to 15 minutes to figure out which directional buttons to use to center it.

I think I will sell the JMI Motofocus and get Moonlight focuser with focal reducer adapter and motor so that the focal reducer is at optimal distance from the camera and closer to rear cell of C-11.

Peter

---

No. Stacking frames reduces the noise. To a certain point, longer integrations are good, but beyond 5 - 10 minutes, you are just making life more difficult for yourself.

Post Extras: