Can't balance scope and DSLR

[Tippon]

I've got a Celestron Astromaster 130EQ MD, and I've been trying to balance it with my DSLR attached for astrophotography. I've got the included weights attached, but I just can't get it to balance while the camera is connected. Is this normal, and I just need to keep tweaking, or will I need extra weights? The camera's a Pentax K-x and weighs 580 g (1.28 lb).

Thanks in advance

[almcl]

It's not that unusual! 

Which axis are you having difficulty with? Both or just one?  

Depending on which, rotating the OTA so that the camera is on the same side as the counter weights can help (better explanation in Making Every Photon Count) or in Dion's video here

[carastro]

If you are talking about needing extra weights I presume it is the RA that you can't balance.   DSLRs don't weigh very much, so you can't be needing much more weight.  I presume you have moved them down to the furthest point.  

If that is the case then you are going to need some extra weight.  I once strapped a pair of pliers to my counterweights to make the RA balance.  Anything small that won't move you can strap to the counterweights save you buying another weight?

Carole 

[Tippon]

Thanks both

In all honesty, I've forgotten which way the scope was turning ? I've had a busy day with a sick three year old, and my brain is fried. I haven't had a chance to get everything set up again tonight, so I'll get it set up in the week and try again. 

I'm pretty sure that I tried the weights in all positions, but I'll double check that too, especially with the advice from the video

[PeterCPC]

I would try it during the day when you can see what you are doing better. When you get it balanced make a note of exactly what you did so that it's easy to repeat it in darkness.

Peter

[Tippon]

Thanks Peter, but I'm doing it in the living room for now. There's been practically zero visibility here this week, so I'm having a general play around and making sure that I know what to do once the stars come out

[noah4x4]

Sorry to say this, and I am not saying it is impossible, but I think you have to be realistic and accept that a Celestron Astromaster 130EQ has amongst the least likely mounts suitable for doing astrophotography with a bulky DSLR.

I suspect that you will suffer from wind-shake and general instability. Balance may be the least of the physical challenges. You might be OK with some short stacked exposures of the Moon, Jupiter and the Orion Nebula etc, but merely keeping your target in your FOV might be very difficult. I owned its predecessor and even with cheap lightweight Celestron web-cams it was very difficult to achieve more than I have described. My advice is give it a go, have a bit of fun experimenting, but don't commit more money unless it is upon a superior mount. It is unfortunate, but this hobby can be very expensive if you aspire to do Astrophotography, and first requirement is having a quality mount.

 

[bobro]

Unfortunately the Astromaster 130 isn't designed to come to infinity focus with a DSLR attached - a common problem. This is due to the distance between the camera's front flange and the camera sensor being more than the scope focuser can adjust for.

You can test for this during the day by pointing the scope at a very distant object (even clouds if they are distinct) and trying to focus.

A 2X Barlow lens may fix the focus but at the expense of worse stability and lower light capture due to the magnification of the Barlow - bad for AP. Alternatively the scope tube could be shortened slightly (been there with a Meade 130, got the badge!).