Starting up.

[Jim Smith]

I'm thinking of trying some video astronomy activity.

Would a SkyWatcher Skymax 127 SupaTrak AUTO 127mm Maksutov Cassegrain Telescope be any use for this or is it too big a focal length on a mount that won't track well enough?  Has anybody tried with this scope?

Or would I be better off getting an equatorial mount for my SW ED120 refractor?  If so, does anybody have any recommendations? I don't particularly need GO-TO on this.  What about an HEQ5?

Thanks,  Jim

[valleyman]

You can  certainly use the Mak for Lunar and Planetary video. No need for accurate tracking for those subjects.

If you need to do long exposer on DSO's then you will need a EQ mount with GOTO and accurate Polar alignment.

A HEQ5 Pro would be OK.

To avoid expense later on go for the biggest mount you can afford. Any OTA would be no good without a rock solid mount.

[Paul81]

For DSO video astronomy the 127 Mak will be far too slow (focal ratio wise) at F11.8. The key to video astronomy is focal ratio - the faster the better! You ideally want to be lass than F6 in my opinion.

The mount is less important for VA as the exposures are kept short - typically 10-30 seconds (although there are no real hard and fast rules). With this regards, an Alt-Az mount is fine, most images on this group are taken using Alt-Az mode. I would recommend GOTO for VA, as you will find it a pain having to keep swapping out the camera for an eyepiece (to find the target) and re-focus (and typically you focus on a bright star, not the DSO in question).

The other nice thing about VA is you do not need top notch optics that are highly corrected and yield a perfectly flat field of view, as the sensors used in VA are typically small (compared to full-on astrophotography CCDs).

With all that in mind, for someone starting out, I'd take a look at something like the Skywatcher 150PDS. It is F5 so pretty quick, a focal length of 750mm so will give a nice useful field of view for most objects, and I see FLO do one on a GOTO EQ mount for around the 540 GBP mark.

In terms of camera, I'll naturally recommend the SX Lodestar and I write some software which you can use to do live video observing with it (see other posts). However, there are other great choices of camera too (watec, mallincam to name a few) which people also get fantastic results with, so we are spoilt for choice nowadays!

[shirva]

hi jim..as suggested a fast scope is preferred, a goto not essential but a tracking mount is..i use a sw eq3 pro with an sw ed80 this set up is more than enough for va,,camera wise an Samsung scb2000 is a great camera if can be bought cheap other than that a camera from phil dyer is perfect..a flip mirror is ideal for setting up the camera focus use a 6mm or 6.5mm lens..davy

[johnno]

Hi Jim

like valleyman stated the mak is ok for planetary, but instead of the expense of the 120 ED about going for a 80ed and a good tracking mount and which camera are you thinking of getting ?  few of use the 80ed and with a 1/3 sensor it seems to be a good combination,

[Jim Smith]

I already have the ED120 scope, so I was hoping that I just needed a suitable driven mount for it. (My current mount is manual alt-az...WO EZTouch).

If its focal ratio of f/7.5 is a bit high can I use a focal reducer?

As for the camera, I really like the shots I've seen on this forum from the SX Lodestar.  Not sure about mono or colour though. Other cameras often seem to show bright stars with a dark ring around them.

[shirva]

I would need to double check but im shure the focal reducer/flat field for the ed80 is the same one for your scope..the shots from the loadstar are pretty impressive paul has done some great work on the software he has produced to make it a formidable camera set up..davy

[Paul81]

I think SW do a 0.85x reducer, and you might be able get more reduction by increasing the distance between the reducer and the CCD.

To be fair I'd give the ED120 a go as is. I guess you will need a driven mount anyway so I'd check out and see what happens, and either get the reducer or a fast scope at a later date!

If you do go for the Lodestar, if getting a monochrome camera I'd stump the extra for the X2. As for monochrome vs OSC, its quite a tough call. Mono (X2 or otherwise) is inherently more sensitive so you are likely to get better detail on the really faint stuff (galaxies). However, the OSC nicely captures planetary nebulae, globs and bright nebulae.

FYI, I will be working on controls to boost the colour in Lodestar Live after the live stacking is finished. At the moment colour comes out quite weak. 

[Jim Smith]

I think it's going to be the colour camera.  As for the mount...I will do a bit more research.  I have a steel pier in the garden with my EZTouch currently mounted on top, so I really just need the mount head (to replace the EZTouch) with no tripod.  That might be hard to come by.  The good news is that if I leave the mount on the pier, I won't have to do a polar alignment every time.

[Jim Smith]

Do the Lodestar C drivers and software install on a Mac?

[Martin Meredith]

Hi Jim

I'm using Lodestar-C on a Mac but run everything via Paul's LodestarLive. The software that came with the camera is Windows only I think. There's also a free application called SXIO for the Mac which I have but don't use.

Unless you're trying to do something exotic I imagine Paul's application is all you need (capture lights/darks, focus/alignment aid, save, real-time image adjustment, dark subtraction), and that works straight out of the tin 

cheers

Martin

[DoctorD]

Hi Jim

Don't dismiss your 127 MAK - I've used both a 102MAK and my C8 with my Samsung SDC435 and my Lodestar-C on Alt/Az mounts - however you will need a foal reducer and the F3.3  SCT one works for both these cameras and scopes, although you'll need the MAK->SCT adapter for your 127.

You will still be limited to the relatively small and bright DSO's but many of the Messier objects will be within your reach.

Integration/exposure times of up to 30 seconds are possible in AZ mode.

I should also add that I have an INED70 ED refractor which complements the C8 and 102MAK.

I use my Lodestar on a Macbook Pro with Paul81's Lodestar live - great for Video Astronomy/Near Real time viewing.

HTH

Paul

[Martin Meredith]

To add to DoctorD's experiences, I use an 80mm achromat at f/6 in alt-az mode and can get to about 1 minute integrations before field rotation becomes noticeable (*). You can go surprisingly deep (mag 15+ galaxies) in that time even with a small aperture and mid-range f value. I'd also consider the new monochrome camera which I guess will be at least twice as sensitive as the current Lodestar-C.

You could also check out DragonMan's home-made focal reducer idea, a cheap way to experiment with focal reduction by a factor of around 0.7 if you have an old pair of binocs you're willing to sacrifice.

(*) since in near-live viewing we're interested in the immediate experience, I think its fair to say that minor artefacts -- vignetting, dust shadows, star trails at the edges etc -- don't bother us too much!

Martin

[Jim Smith]

Thanks for all of the advice.  It sounds like I can start off with the 127 alt-az Mak  (I'll get it down from the loft) and a focal reducer and Lodestar Live on my Mac as long as I don't set my expectations too high.  Then I can get a solid mount and try out my refractor.