The Astronomy hobby thread

[Pazuzu]

Originally Posted by Rusty Heap

they have a "wedge" to move from ALT/AZ to make it a equatorial........I want to do long exposure photowork.........is this the right path and solution ?

You are a glutton for punishment, aren't you?
Here's the deal.
1) Wedges make it even harder to mount the scope (now you have to lift a 65 pound assembly, then tilt it, then balance it, then thread a bolt into it).
2) The wedge itself must be massive to hold the scope. To give you an idea...I happen to have an older Celestron wedge for their early 11 inch scopes. The beer can is for scale. The wedge ALONE weighs about 60 pounds. Now, "modern" design will make it a bit lighter, but still, it's a MASSIVE undertaking.


3) I just, today, picked up a used 8 inch Celestron Evolution with the StarSense camera. I would be happy to flip it to a needy Pelican. No wedge, but you can do 20-30 second exposures in Alt/AZ and use one of the new fangled programs like Registax to stack those short exposures into something longer....

[Eric Hahl]

The C-11 will be a challenge for a newbie doing AP. My suggestion is to get a small, 70-80mm refractor and EQ mount to start. They are much more forgiving of tracking errors while you learn everything there is to learn.

[masraum]

^These guys^ are the experts, but I think a wedge is a cludgy way to go. If you're trying to do AP, which is a precision process, you don't want to be jury rigged.

I had a buddy that had a scope with an alt-az mount and a CCD camera (no wedge). The images that he got weren't great. Anything that wasn't dead center was smeared.

If you were determined to go with that scope, then you'd probably be better off taking the money that you saved by getting it used and using it to buy a decent GEM. (not cheap, especially for a huge, heavy scope like that).

[flatbutt]

A wedge also places stress on drive gears due to the angle. As I said earlier if you're a newb this is big stuff.

[Rusty Heap]

okay all, thank you for your common sense. I'll pass on the 11" ..........

so what's the consensus on the C90? smaller and sanely priced. I don't want to limit myself.


https://seattle.craigslist.org/est/for/d/issaquah-celestron-c90-telescope/7072963474.html

[flatbutt]

I have a 90mm Mak and it is my go to portable. It will give you great lunar views and under decent skies you'll be able to see the phases of Venus, the bands of Jupiter and with good seeing Saturn will pop. The speed is f13.8 and the focal length is 1230. A 25 mm eyepiece will give you 50x and 12 mm will give you 104x. I forget the limit but it's probably online.

With a Baader filter you'll get nice solar views too.

[Eric Hahl]

But.....It's not a great scope for learning Astro photography. If AP is your goal, get a short/fast, ED or fully apochromatic refractor. Something with a focal length of around 400mm or so.
The short focal length will be more forgiving of tracking errors and allow you to up and running taking photos much quicker.
Long focal length instruments need much more stable mounts as they magnify to a much great extent and are generally slower photographically so need even longer exposures which leads to even greater tracking errors.
The point...Start small and with little $, work your way up if your interest stays.

[flatbutt]

Originally Posted by Eric Hahl

But.....It's not a great scope for learning Astro photography. If AP is your goal, get a short/fast, ED or fully apochromatic refractor. Something with a focal length of around 400mm or so.
The short focal length will be more forgiving of tracking errors and allow you to up and running taking photos much quicker.
Long focal length instruments need much more stable mounts as they magnify to a much great extent and are generally slower photographically so need even longer exposures which leads to even greater tracking errors.
The point...Start small and with little $, work your way up if your interest stays.

Absolutely right, I was speaking to visual only.

[masraum]

Years ago, when I was first getting into astronomy, I wanted to get into AP. It seems like yes, you could get in cheap, but for the most rewarding views, you were probably going to end up spending $1500

There are several sites around the 'Net for AP on a budget

https://telescopeguides.com/budget-astrophotography-with-a-telescope-and-dslr-camera/

A decent post at Cloudy nights, the Pelican Parts forum of the Astronomy world.
https://www.cloudynights.com/topic/691497-budget-astrophotography-setup-my-story/

Another interesting site
Beginner Equipment for Astrophotography
https://www.cloudynights.com/topic/691497-budget-astrophotography-setup-my-story/

[Pazuzu]

If someone wanted a REALLY nice refractor...I mean, getting towards as nice as what Eric works with...you could do worse:
https://www.facebook.com/marketplace/item/2823486877670028/
115mm Meade series 5000 triplet APO, with machined rings, WITH the 6000 series reducer/corrector, WITH the 6000 series 2 inch enhanced diagonal...$1000.

I am using all of the strength I have left to not buy it, especially since I'm driving right through his town on Saturday...must not buy...I tried to trade him a mount but he wasn't interested in anything I had...must not buy...

[Pazuzu]

I even have a spare Evolution mount, which means I'd have a GoTo autoguide capable 115mm APO...which I don't need....or want...or need. Or want.

[flatbutt]

Comet ATLAS may put on a good show near Ursa major

https://www.space.com/comet-atlas-may-be-brightenting.html

[Pazuzu]

If you had told me, on the day this thread started, that I would have taken another astro-image in my life, I would have called you a liar.

Yet, here I am, having imaged M3 last night, the first space imaging I've done since about 2003.

Using a client's mount (a brand that didn't even EXIST in 2003...), a CCD that didn't even EXIST in 2003, run through a reflector model that didn't even EXIST in 2003, guided by a webcam that didn't even EXIST in 2003, guiding through a fast focal ratio refractor (that one did exist back then...) using software that didn't even EXIST in 2003.

So weird. Even the idea of imaging with a short focal length reflector and guiding with an even shorted focal length refractor is still so alien to me...when I last did imaging, the CCDs were still barely 1Kx1K (if you were rich...an FLI Dream Machine was around $2000) and 9 or 10 micron pixels. You imaged through an f/7 or longer reflector or SCT (maybe 1400-1500 mm focal length), and guided by hand using a long focal length refractor (1000+mm) or an off axis guider. The CCD chips were small, low resolution, B&W and had fat pixels (we never thought that they would ever even APPROACH film grain...). No plate solving, no autoguiding, no multi-night imaging, for SURE no combining data from different camera/scope setups...LRGB was just really gaining steam, no narrow band stuff (the chips just weren't sensitive enough).

Now, you can buy a single shot color CMOS camera for $300 that will decimate anything I did back then.


The only thing that I don't like about the image is there's some strange artifacts...

Eric will understand. I did this using the free version of Nebulosity, they...um...watermark the images until you pay for the full version. I mean, they watermark ALL of the images. Darks, lights, everything. So, ignore the watermarks from 15 darks and 15 30 second lights.

M3 Globular Cluster, Apr 2020
15x30 darks, 15x30 lights, no flats
Meade DSI-Pro I CCD camera, IR block filter
Celestron Omni 150mm f/5 reflector
Guide camera Phillips SPC900NC webcam, 0.5 reducer
Guide scope Orion ST80 short tube 80mm f/5 refractor
iOptron iEQ45 Alt/az mount on an iOptron pier
Guided using PhD2, imaged using Nebulosity 4.0

[RNajarian]

Originally Posted by flatbutt

Comet ATLAS may put on a good show near Ursa major

https://www.space.com/comet-atlas-may-be-brightenting.html

Looks like out show got broken up. . .

https://www.foxnews.com/science/comet-disintegrates-in-remarkable-pictures-captured-by-nasas-hubble-space-telescope

Too bad, I was hoping to see it

[masraum]

Originally Posted by Pazuzu

If you had told me, on the day this thread started, that I would have taken another astro-image in my life, I would have called you a liar.

Yet, here I am, having imaged M3 last night, the first space imaging I've done since about 2003.

Using a client's mount (a brand that didn't even EXIST in 2003...), a CCD that didn't even EXIST in 2003, run through a reflector model that didn't even EXIST in 2003, guided by a webcam that didn't even EXIST in 2003, guiding through a fast focal ratio refractor (that one did exist back then...) using software that didn't even EXIST in 2003.

So weird. Even the idea of imaging with a short focal length reflector and guiding with an even shorted focal length refractor is still so alien to me...when I last did imaging, the CCDs were still barely 1Kx1K (if you were rich...an FLI Dream Machine was around $2000) and 9 or 10 micron pixels. You imaged through an f/7 or longer reflector or SCT (maybe 1400-1500 mm focal length), and guided by hand using a long focal length refractor (1000+mm) or an off axis guider. The CCD chips were small, low resolution, B&W and had fat pixels (we never thought that they would ever even APPROACH film grain...). No plate solving, no autoguiding, no multi-night imaging, for SURE no combining data from different camera/scope setups...LRGB was just really gaining steam, no narrow band stuff (the chips just weren't sensitive enough).

Now, you can buy a single shot color CMOS camera for $300 that will decimate anything I did back then.


The only thing that I don't like about the image is there's some strange artifacts...

Eric will understand. I did this using the free version of Nebulosity, they...um...watermark the images until you pay for the full version. I mean, they watermark ALL of the images. Darks, lights, everything. So, ignore the watermarks from 15 darks and 15 30 second lights.

M3 Globular Cluster, Apr 2020
15x30 darks, 15x30 lights, no flats
Meade DSI-Pro I CCD camera, IR block filter
Celestron Omni 150mm f/5 reflector
Guide camera Phillips SPC900NC webcam, 0.5 reducer
Guide scope Orion ST80 short tube 80mm f/5 refractor
iOptron iEQ45 Alt/az mount on an iOptron pier
Guided using PhD2, imaged using Nebulosity 4.0

Technology marches on at an ever increasing pace. Good image, but the artifacts are odd, especially since they seem to be throughout the image, not just on the cluster. Did the individual images have them or is that something introduced by the stacking software?

[Eric Hahl]

The dark streaks are the watermarks correct? The lighter area on the bottom is the artifact...amp glow? That's really a great image and testament of your focusing skill with that 150 F5!

[Eric Hahl]

Shoot, I forgot to post this here. The other day I advertised a great visual telescope for sale on cloudynights and astromart. Here's the ad...Asking $2900

I've got a perfect Tak FS-102 with a Starlight Instruments MPA-TAK2.7 micro focuser and Twistlock adapter for 2" for sale.
The scope is near perfect in cosmetics and excellent optically.

Included:

Scope with SI MPA focuser, twistlock, rings, mount plate, caps, red dot sight. (I might have a soft travel case for the scope. Will have to check). Diagonal in not included.

Losmandy GM-8 Digital drive mount with all cables, controls and one counterweight. Works perfect and is in excellent condition. Looks like its barely been used. Will include an Orion Dynamo pro power supply.

Paypal fees included but buyer will have to pay for shipping.

[Pazuzu]

Originally Posted by Eric Hahl

The dark streaks are the watermarks correct? The lighter area on the bottom is the artifact...amp glow? That's really a great image and testament of your focusing skill with that 150 F5!

Here's a single raw, with the levels set to show the watermarking, dust, vignetting, and dark noise. The watermarks are (of course) dithered, so they don't go away with dark subtraction or stacking...

I paid for the full version, I'll see what I can do this weekend with it.

[Pazuzu]

Tonight's rig. Thin clouds have taken over, but that's OK because I'm mostly testing this mount before I give it back to the client. A couple hours of guiding even through thin clouds is plenty.

[Eric Hahl]

That's a nice setup right there!