Finderscope For Guiding?

[pjphilli]

Hi
When I use my Meade 80mm f6 refractor for imaging I then use my 150mm Mak f6 for guiding. This works OK but it becomes a nuisance when no suitable stars appear in the Mak's FOV as it is difficult to re-orient the scopes (which are normally collimated) to get a suitable star on the guidescope. I see my 50mm f5 finderscope sitting there idle on its adjustment rings and I wonder whether this would be suitable to use as a guider with my Meade 80mm imager? I would like some comments before I start experimenting. I have already shown that I can focus my DSI Color camera on the above finderscope. I use PHD guiding software.
Cheers Peter

[gbeal]

If it helps, I too have a similar setup.
My imaging scope is an 80mm f6 refractor, sometimes with a 0.8x reducer/flattener. I have a 65mm/500mm guidescope, and it works a treat, but of late I have been using part of a simple 8x50mm finder-scope. I unscrewed the eyepiece end and made a fitting to hold my QHY5, and this will be not unlike your DSI. Works a treat, all indications say it shouldn't, but it does. Try it and see, I am sure you will be pleasantly surprised. I have used mine with PHD, although mostly I use it with Maxim DL.
Gary

[g__day]

I pondered doing this with either a normal or a giant Lumicon finder scope (80mm) - these accept 1.25" eye pieces so adding a meade DSI = easy!

Mind you this give you a only a 300mm focal length system (maybe use a 2x barlow?) with 3.8 degree field of view. I was tossing this up for remote viewing to check where I was pointing with a second CCD until I nailed the pointing problems.

http://www.lumicon.com/astronomy-accessories.php?cid=3&cn=Finder+Systems

[gbeal]

Still reckon try it anyway Matthew, in my 80mm case it works well. In the project pile at present is a re-tube (well truss) of the 10" f5, and I think I will be pushing it to get the humble 50mm finder *******ized to guide with 1250mm of scope. Then I may have to go to the 65/500 guide-scope after all.
Gary

[AlexN]

thats a novel idea... I have 2 8x50 finders wishing they still saw action... Might give that a go! Can't hurt to try it i figure

[pjphilli]

Hi
Thanks for the replies - sounds like guiding with my finderscope will be worth experimenting with during the next bright moon cycle.
Gary - I see that you have used PHD but are now using Maxim DL. I have found PHD is very easy to use and its real time graphing is a big advantage.
My DSI Color camera is not very sensitive even when I use it on mono for guiding. Also when I have the camera running on its normal Envisage software I can usually see a few fairly bright stars but when I go to PHD very few stars show as if PHD does not have sufficient amplification?
Is Maxim DL better in this respect? and does it have real time graphing?
Cheers Peter

[gbeal]

Peter,
try it, even at the start/end of a night where you have 5 minutes, or as you say experiment during the moon impinging on the imaging.
In answering what I think you are asking, I seriously doubt the different software will account for the perceived lack of sensitivity. I use a QHY5 mono for guiding and normally use about a 2 second exposure.
My biggest driving force for Maxim over PHD is that when I use PHD, I can't connect to TheSky for some reason, a conflict of the port I use, so in that respoect Maxim is simpler. This is 99% operator error rather than anything else, but right now Maxim does it, and has a tracking graph as well.
Gary

[g__day]

Having used both (PHD for quite some time), I think Maxim is more advanced and feature rich if you want to try tweaking things. I'd posit that PHD has a better readout screen and its easier to pick guide stars (so the interface works well), but I think Maxim's engine is more slightly powerful and capable.