Teething Issues

[Chif]

Good Evening All,

I've been experimenting with my new setup over the past couple of months but am having a few constant issues. I was wondering if anyone here had some thoughts or advice.

First of all, I am having a very hard time getting a decent alignment. I've spent hours at a time on this and don't feel I'm getting any closer. I'm using a canon 400D, which does not have live view, prolonging the time it takes me to get the stars moving across horizontally. Also, as I'm using a bintel astrograph, I cannot get an eye piece in focus, so an illuminated reticle may be out of the question.

Also with alignment, I have had instances where I will make an adjustment, and the drift seems to stay moving the same velocity (even after drastic adjustments).

Also, when it comes to balancing my equipment, obviously as the scope rotates etc, the balance will be different to how it was original set up. I can tell when this is the case, because the mount (CGEM pro) will move faster, or shudder under the load. Is there any way to combat this?


If anyone has some advice for me, that would be great, and let me know if you need any more info!!

Thanks a million,

Andrew.

[glend]

Well Andrew there appear to be a few issues there. When you say a Bintel Astrgraph exactly which one ? It's not unusual for an astrograph config to fail to achieve ep focus unless an extension tube is used. Did you try the ep with an extension tube. It is pretty much impossible to focus a dslr without either Liveview or BYEOS conected to the camera. How is it setup. I assume you are not using a guidescope and guide camera at this stage. Short exposures can be done if your alignment is close. How did you setup the mount? More info is needed to help sort it out but iit can be done. Btw if the mount is shuddering it is likely binding, has this mount worked for you in the past?

[Chif]

Hi Glen,

Thanks for the reply. The astrograph I have is this one here:

http://www.bintel.com.au/Telescopes/Cassegrain/Bintel-GSO-RCA-150-f/9-Astrograph--Steel-/601/productview.aspx

I have previously tried to use eye pieces using the extension tubes provided, but they weren't long enough.

I am using backyard EOS, but it's still taking long without live view. I'm not using a guidescope yet, no. The first night I tried I was able to get about 6 second exposures with no issues, 10 seconds was OK, anything higher was no good. Am I better off getting a guide scope? Or perhaps a camera with live view to help getting my alignment downpat.

I have only just got this mount off another user here. The first few times I used it, the speed was very consistent, however lately it speeds up and slows down a bit.

[billdan]

Gooday Andrew,

I don't know why you think the mount is speeding up and slowing down, you have very little weight on it to overload it.
These mounts do have a periodic error of about 15 arcsecs ( speed up for 7 arcsecs and then slow down for 7 arcsecs ) but it would be not noticeable to the naked eye unless you were at 400x mag. At prime focus with the camera installed, which is at the scopes lowest mag (about 20x) you shouldn't notice it.

It could be a dodgy power pack that you have though.
Even if you are grossly unbalanced, with the low amount of weight you have on the mount it shouldn't effect it.

To give yourself an idea how far off your polar alignment is, try this, park the mount and turn it off. It should be now looking directly at the Sth Celestial Pole. Then with the camera installed take a 10 or 15 minute image and look at the star trails. If the polar alignment is correct the centre of the concentric rings should be at the centre of your camera image.

Similar to this image attached ( even though this photo is the Nth Pole, same principle applies).

If its close you can then go back to drift aligning to tweak it, but you will probably need to get that extension tube sorted first and use an eyepiece. Remember you are looking for movement in Declination or N-S movement.

You will be probaly get a guide scope and camera eventually (we all do), but for now get the polar alignment sorted first and see how long you can take a drift free image, you should get at least 30 to 60 secs.

Regards
Bill

[glend]

Given that it's an RC I will suggest it is out of collimation and perhaps your not using the right combination of tube extensions. On my RC08 I have to use one 50mm and one 25mm extensjon tube screwed on the back plus my collimatjon ring and focuser to achieve focus with my camera. Please tell us know how you have the back end setup, a photo would be good. Maybe another RC06 owner can suggest the correct arrangement for your scope.
RCs can be a hard scope to learn on as they are time comsuming to tune and always require collimation tools. However if you take the time to setup your RC it will be a nice image platform. I'd suggest you get the RC to focus visually as a first step. Stick on all the tube extensions and see if you can get a fairly wide low power ep to focus, you may need to stick on a small ep extention tube in the focuser. Then you can judge the collimation visually, and use that to aid your alignment setup.

[Chif]

Thanks again Glen and Bill. I have been able to get an eyepiece to focus, but that was with all tube extensions in place and the eyepiece was too far back to be secured with the thumb screws, so an EP extension might be the way to go. I'll work on getting that sorted and I'll give the star trails a go as well.

Thanks for all the help so far, I'll keep you guys posted. I've packed up all my gear for now but will take some photos when I set up next. :)