HA! I see what you did there.

At Goodwill store, I just picked up a stack of couple year old Sky and Telescope mags for 50 cents each.

danger danger says the Visa Card.

Nice!

https://lifehacker.com/how-to-take-advantage-of-the-black-supermoon-for-optima-1836792145

OMG guys! A Black SuperMoon! Which is just the second new moon of the month...which happens twice a year every year...and is as dark as...well, every other new moon, ever...

WTF is the purpose of this article?

None, but a new moon is ideal of course.

for you wizards of the stars.


I've always wanted a Dob.


This one, motorized, for under $900.


cheap crap, or a good "big" scope?


https://www.telescope.com/catalog/product.jsp?productId=102013&gclid=CjwKCAjwm4rqBRB UEiwAwaWjjGvw4EcaZvaHYfRLO45pp4PF59SpTfGBaF2yp92R3 SThWqclMtA8-RoCNakQAvD_BwE


suggestions for this or others along the same vein and price point.

Rusty, Orion is a good brand in general. The Dobsonian design is a bit unwieldy for some people so be advised on that bit. The GOTO computer is nice to have but you will need to align the scope with a reference point such as Polaris in order for it to be useful. Overall that Dob is probably good enough for visual observing but you can probably find a used one at a much lower price. my .02


you can peruse places like this: https://www.cloudynights.com/index.php?app=classifieds&do=view_category&categor y_id=&sort_key=date_added&sort_order=desc&filter=0

100% agree with the above.

Rusty, it's not motorized. It's a "push-to". It's got sensors and a computer that you calibrate (each viewing session) most likely by pointing the scope at 2-3 specific big, bright stars. Then you manually move the scope around and via some mechanism, it tell you "warmer, warmer, getting hot, there it is!"

I think you can pick up the version that's not a GOTO for $629. To me, it would be much, much better to save the $270 and just star hop. You can then spend the extra $270 on eye pieces, barlow, etc.....

It looks like Zhumell is hardly around any more, with Orion dominating, which is probably why the price has gone up a bit.

You'll likely want a 2X Barlow and a couple of eye pieces. I went with hyperion eye pieces which were good kit at a decent price. Shoot for being able to get whatever scope you buy (assuming you go with 8" or 10") to about 250-350x mag (max). I think I was able to get to 300x and did occasionally get good views, but most of the time, I was in the 75-225 range, IIRC.

I was even able to watch an ISS pass in my old dob once. It was low mag and tough to keep in the eye piece, but super cool.

Why?
I'm asking, because normally one would get a dob because they want the most aperture per dollar, and will give up everything else for it. GoTo systems never work well with them, either they're basic push-to systems like the one you showed, or they're really expensive, finicky things that you need to balance perfectly.

I've had dobs before and always gotten rid of them, too much work.

Hell, I have an 8 inch Orion dob sitting in the garage right now that I planned on parting out, it came with a package that I bought. Too bad I don't know any Pelicans that want an 8 inch dob...

Unfortunately, I'm not in the market to replace my old 8" that I sold to move.

I got outside last night and shot the North American and Pelican nebula's in Cygnus. 4.4 hours worth of exposures. Messed up the flat field images I took for calibration so didn't include any in this picture. They sure would have helped. I've got a weird color gradient I don't care for. Oh well, chaulk it up to learning.

https://cdn.astrobin.com/thumbs/YwAtyx8kmoAS_1824x0_wmhqkGbg.jpg

I'll say two things...
The only time I saw variation like that (top to bottom symmetrically) was electronic heat along the "reading" side of a parallel CCD. Not a serial CCD, which reads row after row then shifts the register down, since that creates corner heat. Parallel read CCDs read each column at the same time, so the read noise is across one edge. It's not optical, clearly. That was old school mono CCDs, I have no idea how modern full color CCD/CMOS chips work. Maybe they're all parallel now.

You over processed, you made halos around the stars in the nebula. Now, if you go back and look at my old images, I generally did the same thing and was fine with it, but since you're now vanguarding the imaging in this thread, we're all looking to you to BE PERFECT. :)

Edit: It sickens me to to see what some freaking amateur can do these days with 4 hours of imaging. All those hours I spent guiding by hand in a reticle eyepiece, eyes fogging over because you're hunched over cutting off the blood to your brain, then taking that roll of film to the only shop in town that won't destroy your images, only to find out that your guide camera was out of balance and slumping during the run, and your image was ruined. We EARNED our bad images back then! :p

Yes, you definitely earned them with film and manual guiding. lol.

Yes, definietly a heat problem. I had the cooler set for -30c below ambient. I might be able to get a hair more with this camera but it will be sucking up 100% power to do it.

This is the camera I'm using...https://www.atik-cameras.com/product/atik-16200/

and the filter wheel....https://www.atik-cameras.com/product/atik-efw2-2/

and the Off axis guider...https://www.atik-cameras.com/product/atik-oag/

So, it's a mono camera running at -(40-50) CELSIUS? Then it's probably not normal heat. (Edit, I see you said -30, but still, that's 60 degrees!)
Could the chip be seeing the electric board? I guess a flat could have corrected for that. Man, they're cramming so much power into such a small housing these days, the dark/flat/bias signatures are completely different than what I'm used to (from 15 years ago, when that camera would have only existed in research situations...)

The cooler gets the temp down about -50F from ambient. So, if its 80f outside the sensor can get down to 30f.
I was doing some long exposures (10 and 15 minutes) and it definitely shows amp glow from the sensor on the top of the picture. For this particular shot, the hydrogen and oxygen were shot on the east side of the meridian and the sulfur was shot on the west side so I got the glow both top and bottom.

I'm going to try shorter exposures with a break in between shots to cool the chip down each exposure and see what happens.

Thanks for the advice!

Did you take any darks or biases? What do they show? Do you have any flats, even if they're bad?

I do have darks and bias, both from another session so maybe not a great fit. Flats and bias are both short exposures and do not show the amp glow or current. Might get out and try again tonight to verify amp glow.

Finally made the jump to being a Vendor there.