M22 Globular cluster in Sagitarius

[Robert_T]

Hi All,

First picture for quite a while. I've been trying to get my polar alignment and auto-guiding working sufficiently well to warrant actually exposing stars.

It's still not really working well though I've had some improvements. This one was from the best 7 of 17 x 100s exposures with the Canon 40D at 800iso through the York Optical ED80 and 0.8x reducer. Even with just the best 7 and short exposure the stars still aren't round. I'm getting a little discouraged with the LXD75. I'd really love to run longer deeper exposures and use slower less noisy ISO.

No flats just darks for this. Processed and combined in Images Plus and then tweaked up and cropped (to get rid of vignetting) in Photoshop CS3. The off centre composition is deliberate - trying the rule of thirds on astro ;-)

Anyway, here it is:) comments and advice welcome.

cheers,

Rob

[renormalised]

Rob, you need an EQ6 Pro mount....much more stable.

[Robert_T]

The LXD75 has 2in stainless tripod legs and with just the ed80 is plenty stable... what i need is tracking accuracy... tell me great things about the EQ6 on tracking;)

[Dennis]

Nice work Robert, and welcome to the maddening, at times futile world of chasing round stars! M22 is one of my favourite globulars and always surprises me with its size and brightness whenever I take a peek.

Cheers

Dennis

[AlexN]

Robert, Nice image, the exposure seems to have been enough to bring out colors and a bit of depth in the image..

I bought the EQ6 based on a lot of people who use them for imaging saying that its best option for the price and that its go-to/tracking is great....

Probably not the most convincing way i could tell you to spend 1500 of your hard earned.. but it was enough for me... :D

[[1ponders]]

Rob, I gather your LX75 doesn't have an autoguider port. Any chance of finding the accessory that allows you to do that? Either that or head on out to Duckadang during Astrofest and I'll give you a quick run through on using K3 for polar aligning. ;)

[Tandum]

Rob,
I can't fix your guiding but this might take care of your vignetting.

I found any sort of flats fixed my images a lot, so, something to do on a rainy day, with about $40 in bits for my scope, probably 1/2 that for yours, make a light box.

The box is foam board from office works (comes in 770x500 sheets for $12), plexiglass from a glasier in moss street (255x255 was $10, cut while you wait) plus 4 white LEDs, a limiting resistor and power socket from dick smiths (Under $10) and a link to work out LED limiting resistors (priceless). http://www.quickar.com/noqbestledcalc.htm

Hot glue gun, box cutter, ruler and I used black silicon to light seal the joints at the end although gaffa tape may have been neater. I have it so it plugs into the mounts 12v supply. You could easily make different sized entry plugins for different scopes. It simply pushes onto the end of the scope, it's pretty light.

Mine has a 220mm opening and is 200mm deep. I've since read that the depth only needs to be 70% of the opening but I just planned mine around 2 foam boards cos that is what I bought :)

No photos using it yet, I don't have my astro camera at the moment, so I'm not sure if using white LEDs is the way to go or not. However they only have a 15 degree light spead so I didn't need any internal baffling to keep direct light off the diffuser. I simply bent and hot glued their legs, pointing the lens to the back/top of the box.

It's based on -> http://www.gregpyros.com/html/light_box.html His uses drafting mylar as an initial diffuser internally but I went to a drafting supplies shop and that stuff is obselete. They could get it from the vault in Sydney, but not one sheet. They gave me some drafting tracing paper which looks the same optically, but it would tear if stressed. I didn't bother using it as I didn't use normal light bulbs.

I'm hoping I can use it to set a custom white balance to sort out that Astronomiks CLS filter I bought and to be honest, any flat is better than none.

[AlexN]

Nice light box Robin... :) I'll be hitting you up for a hand making one of them soon enough!

[Robert_T]

Thanks Guys,

Nice light box robin, I'll have to get off my behind and make one of those:thumbsup:

Yeh Paul, no autoguider port on the LXD75. I'm guding using ASCOM into the autostar handcontroller. I reckon I've got the polar alignment pretty close. I've left the mount out under a tarp and try and tweak it a bit more each time I go out periodic error with drift align (hard with my horizons) and backlash. It seems more an issue now with "oscillation" and/or the way PhD corrects for it (and I've just about worn PhD out tweaking the various aggressiveness settings etc). I have started training the PEC. I think a few more updates might be needed though. Haven't quite given up:whistle:

Astrofest unlikley for me I fear this year:sadeyes:

cheers,

Rob