A frustrating afternoon and evening

[centroid]

I spent the afternoon preparing my set up. for a first light session. First job, lining up the 50mm finder scope with the new 115 APO.

Then Attached the 294C to the 115, and took an image of distant TV aerial, no problem. Second job done.

Next I attached the GPCAM 130 to the OAG guide port. I then spent the rest of the afternoon, trying the focus an image via the prism, without success. Multiple prism positions tried, and multiple guide cam to prism positions tried, but zero success. In fact I couldn't even achieve an out a focus image. In the end, I gave up in despair. 🙄

Another try after dark, but another couple of hours wasted. ☹️

I am now seriously taking what to me is a retrograde step, and going down the guide scope route.

The irony is, in my previous astro imaging days, I used an OAG with an SX Lodestar for several years, without any problems. I can't remember what make the OAG was, as it was 8 years ago, but this one I believe is an OVL one, which I recently purchases from FLO.

Edited October 3, 2021 by centroid
typo

[centroid]

Two potential candidates for a 60mm Guide Scope. The Altair at £139, or the SvBONY at £99. Both come with mounting rings, and probably from the same Chinese factory 🙂

Anyone used either of these, and if so how do you find them?

https://www.amazon.co.uk/Svbony-Helical-Focuser-Astronomy-Telescope/dp/B07N1BDPL4/ref=sr_1_4?adgrpid=53680609416&dchild=1&gclid=CjwKCAjwzOqKBhAWEiwArQGwaGg-K1fLB-X6cxGnrO8Yo90aUECn97NtAZAsfVNFoxJAWCELFnbxQRoC5UgQAvD_BwE&hvadid=259009923519&hvdev=c&hvlocphy=9045050&hvnetw=g&hvqmt=e&hvrand=6489284136323683334&hvtargid=kwd-315665898231&hydadcr=3952_1711725&keywords=guide+scope&qid=1633340101&qsid=258-8932162-1151919&sr=8-4&sres=B08927JRBJ%2CB07N1BDPL4%2CB07NPF5PXM%2CB06X15NDTV%2CB0826NYCH1%2CB071J2TRP3%2CB00DEOM534%2CB0811JK7W4%2CB08LDKD8ST%2CB001TI9Y2M%2CB07RQT5CHV%2CB07CB14GZL%2CB01N3KODZ6%2CB00K0O1SJ8%2CB098FD8MGF%2CB093FQGVGZ

https://www.altairastro.com/altair-60mm-guide-scope-kit-straight-thru-non-rotating-helical-focuser-no-eyepiece-76-p.asp

Edited October 4, 2021 by centroid

[michael8554]

With any brand of OAG:

Roughly measure the distance from the centre of the prism to the main imaging sensor.

Attach the guidecam that same distance from the centre of the prism.

Focus the imaging camera on a distant landmark.

Without altering that focus, now fine-focus the guidecam.

Don't ever change the guidecam focus -  if the main camera focus is now set on stars, the guidecam will always be in focus too.

Michael

 

[centroid]

I tried every possible combination Michael, including your suggestion, without even getting near to success. As I said earlier, I used an OAG before, and getting it set right was straight forward.

Thank you for your input, but I think I am going to be heading down the guide scope route.

Unlike before, when I had an observatory and attached warm room, everything was close at hand. Now its pier in the garden, with every controlled from the summer house, via 5m cables. So instead or just opening the observatory, and switching everything on, I now have to attach the mount to the pier, and then add the scope etc.

Edited October 4, 2021 by centroid
typo

[michael8554]

If you have the imaging and guidecam distances the same, all I can think of is you don't have the prism far enough into the light path.

Try with the prism as low as possible, then work out until the prism shadow no longer shows in Flats.

Michael

[tomato]

Sorry if this sounds a bit agricultural, but if you can have your screen next to the scope and OAG, with the main scope in focus, can you move the guide camera in and out by hand while watching the screen, you might at least catch the point close to focus.

Apologies if you have already tried this, it worked for me on one desperate night, I had the scope pointing at the moon so there was a nice bright target.

[Craig a]

I ditto what tomato said, I did the exact same thing when setting up my zwo OAG, pain to setup but one done it shouldn’t need doing again 

[newbie alert]

As said in the above comments, the main camera and the guide cam need to be at the same distance from the prism taking into account they both have diffent backspacing

You never mentioned about spacing ,that's dictated by your scope and if using a reducer it should be 55mm

Another thing to do is to have the long side of the guidecam with the long side of the main imaging camera

The lodestar is a heck of a guidecam, alot more sensitive than the 130 but I'm sure it's capable if picking up guidestars