first go at Triangulum galaxy, question about camera focus

[funkysandman]

First time seeing the Triangulum through the scope (Celestar 8 deluxe) - problem I'm having is focusing; I find the object in the ocular then switch to a t-ring and slap on the camera but now it's out of focus.  I have to find a nearby bright star to focus and then I have a helluva time finding the DSO again.  Any advice?

[Tinker1947]

A Bahtinov mask will sort out the focus......

http://www.firstlightoptics.com/bahtinov-focus-masks/starsharp-bahtinov-focus-masks.html

[pipnina]

Is there a finder on your scope? Something like a red dot finder or a 9x50 RACI would work wonders for you. you could even help frame targets by taking a test image or two and see if the object is in fact there.

[StargeezerTim]

Have you got a goto mount? If you have, you can 'save' the location, go to a bright star, focus, then go back. Alternatively, find a bright star first of all, focus, then go the object with your goto. then take a 60 sec image with right iso to see if you are in the right place, then adjust. 

Without a goto feature, it will be very difficult and fiddly as mos DSO's dont have stars bright enough to get a good focus on, even with a Bhatinov mask.

Nice image...

[funkysandman]

Have you got a goto mount? If you have, you can 'save' the location, go to a bright star, focus, then go back. Alternatively, find a bright star first of all, focus, then go the object with your goto. then take a 60 sec image with right iso to see if you are in the right place, then adjust. 

Without a goto feature, it will be very difficult and fiddly as mos DSO's dont have stars bright enough to get a good focus on, even with a Bhatinov mask.

Nice image...

thanks,no goto mount, just doing it manually.  I can't see anything on the camera's display because it is too faint, so I'm not sure if the mask would make any difference

[salas]

What camera are you using? If a star seems to faint you may be able to zoom in using the camera screen for a better view. Then go to a nice bright star like vega, and use a Bahtinov mask to focus. I cant recommend a mask enough it made my life so much easier!!!!

[PeterCPC]

If you are using a Canon DSLR I suggest that you download Backyard EOS as a trial and see if that helps.

I suggest focusing on a nearby star with the Bahtinov mask and the camera attached. Then move to where you think M33 is and take a 60 sec or more exposure and see where it appears on the laptop screen. You can then nudge the scope to make central.

Peter

[D4N]

The way you use a bahnitov mask if live view is too faint is to set gain (ISO) to maximum and take an exposure of say 5 seconds, hopefully you have bright enough stars to focus on if not up it to 10. Note which side of the star the off centre line is on and adjust the focus then take another exposure. If the line moves the closer to the star move the focuser the same way again, if it got further off centre or went past the star turn the focuser the other way. Repeat until it's spot on.

After a bit of practice it gets pretty easy to focus this way as you learn to judge how much to turn and in what direction.

/Dan

Sent from my iPad using Tapatalk

[funkysandman]

using a Canon 70D, and I have to zip over to a bright star to find focus, then try to relocate the object.  I use the quick exposure / high iso to see if the object is there, but if it isn't, it's  painfully trial and error ...not getting easier as it gets colder!  I'll have to get a hold of one of those masks and try that out

[Tinker1947]

thanks,no goto mount, just doing it manually.  I can't see anything on the camera's display because it is too faint, so I'm not sure if the mask would make any difference

You really should think about a GoTo mount you imagine output will go up 10 fold, focusing will never be a problem as you use a bright star then GoTo you DSO, its really that simple once you get to know how it works.....

[michael8554]

As already suggested, focus on a nearby bright star on the camera using Liveview, ideally on a monitor, magnify for the final tweak.

Set your setting circles on the RA and DEC of that bright star, then move to the DSO's co-ords.

Take a 30 second exposure at Small JPG and highest ISO, then Platesolve the image using Platesolve 2 - free download of the prog and star catalogue at Planewave Instruments.

That will tell you where you really are, then nudge to correct location.

You don't need GoTo, spend it on a F6.3 reducer.

Michael

[funkysandman]

Yeah,got a reducer/corrector on the way. I'll check the platesolve. Thanks

[funkysandman]

I'll be involving the laptop now I guess

[Pompey Monkey]

I'll be involving the laptop now I guess

If you're involving the laptop, I'll second the recommendation for using platesolving.

I use Astrophotography Tool (APT) with All Sky Plate Solver (ASPS). I don't even have a finder on my AP telescope now!

ASPS will solve your images blind i.e. without knowing even roughly where your scope is pointing, whereas PlateSolve2 requires approximate coordinates of the where you are pointing to work.

There is a bit of a learning curve to eventaully get it all going (isn't there always?), but take it in steps and it's worth it.

[D4N]

Plate solving on a non-goto mount will require good setting circles though otherwise it will be an exercise in futility.

I know the setting circles on my old EQ2 were basically just decorations, they were useless when it came to using them.

I have just realised that you scope is f10 with over 2m focal length, no wonder it is hard work!

/Dan

Sent from my iPad using Tapatalk

[funkysandman]

As already suggested, focus on a nearby bright star on the camera using Liveview, ideally on a monitor, magnify for the final tweak.

Set your setting circles on the RA and DEC of that bright star, then move to the DSO's co-ords.

btw, is there something I don't know about the setting circles?  I set the RA wheel as close as I can tell, but it doesn't seem to have the finer resolution for what I need - I just have to eyeball it.  The DEC wheel on the mount seems accurate to about +/- 0.5 degrees at best.  It's like a car that has a speedometer that only has a few numbers..

[D4N]

That sounds about right, the ones on my EQ2 were more like a speedometer with only a few numbers that were also in the wrong place and had a propensity to rearrange themselves inbetween uses.

Some mounts have good setting circles, many do not.

/Dan

Sent from my iPad using Tapatalk

[michael8554]

We're talking about a Celestar 8 here, not an EQ2.

The RA setting circle is about 8" diameter, the DEC 4 to 5" diameter, I don't find them an exercise in futility on my similar design Meade LX.

The process works exactly like, and as easy, as I posted.

Michael