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4D
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« on: Tuesday, August 15, 2023, 10:45:50 »

Just started a new hobby to go alongside car modifications.
Bought myself a dobsonian telescope with an 8 inch aperture, already have a dslr camera I can attach for astrophotography. There's a lot to learn, so if any of you have experience then please pass it on  Smiley

Here's the beast....



* 20230813_220902_copy_744x1612.jpg (243.04 KB, 744x1612 - viewed 116 times.)
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Wobbly Bob

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« Reply #1 on: Tuesday, August 15, 2023, 11:06:55 »

Fuzzy is yer man.

I've only got as far as the DSLR camera stage, but that looks like a serious piece of kit.
Enjoy!
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BambooToTheFuture

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« Reply #2 on: Tuesday, August 15, 2023, 12:03:51 »

Someone's sitting there mate...
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You smell the gunpowder and you see the blood, you know what that means?
It means you're alive. You've won.
You take the heads so that you don't ever forget.'
fuzzy

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« Reply #3 on: Tuesday, August 15, 2023, 13:33:22 »

Just started a new hobby to go alongside car modifications.
Bought myself a dobsonian telescope with an 8 inch aperture, already have a dslr camera I can attach for astrophotography. There's a lot to learn, so if any of you have experience then please pass it on  Smiley

Here's the beast....



A Dobsonian is a great starting scope- your get more bang for your buck (where bang = the size of the hole at the front of the scope). The bigger the hole (objective) the more light it gathers so the more you can see and higer you can magnify.

Magnification is done with the eyepiece. A rough guied to the magnification is to divide the focal legth of the telescope (marked in mm on the black sticker you can see) by the focal length of the eyepiece so, if yours is a 200mm/ 8" Dob, the focal length will be around 1200mm. If you have a 25mm eyepiece, the magnification will be 1200/ 25 = 48X.
A 10mm eypiece will give 12X magnification.

Be careful with magnification however. Shorter focal length eypiece reduce the brightness/ contrast of the image and also image quality falls off with higher magnification.

With using a Dobsonian for astrophotography, be aware of star trailing. With a mount like the Dobsonian, you move in altitude (pointing the scope higher or lower in the sky) and azimuth (rotating the scope from left to right and back again), known as an alt/az mount. The sky doesn't "move" in quite that fashion. It doesnt move in a parallel semi circle in relation to the horizon. It arcs from a point in the east, over your head and down to a point in the west. This means that if you have the shutter open too long, the image will trail or blur.

Maximum shutter speed for alt/ az mounts (or undriven equatorial mounts) can be worked out with another bit of arithmatic- 500/ focal length so, 500/1200 gives a shtter speed of just under half a second. Ramp up the ISO and give it a go on stars etc. For the moon, half a second will be too long. get out therer and play- though I have a feelingt that the recent cloud cover must be your fault for buying a new scope.....  Cheesy

Lots of good advice etc. on here- https://stargazerslounge.com/
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4D
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« Reply #4 on: Tuesday, August 15, 2023, 13:40:42 »

Cheers fuzzy. Yes, it's a 1200mm focal length. Just ordered a moon filter and the Turn left at Orion book.
I know what you mean about the movement, I focused on Saturn with a 25mm wide angle, went in to get the missus to take a look, and it had gone  Cheesy
The finderscope doesn't seem to be aligned so I need to look at that. I have ordered a laser collimator as I think the primary/secondary alignment is slightly out.

I have 6mm, 10mm, 15mm, 20mm and 25mm lenses. Plus a 3x Barlow.
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fuzzy

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« Reply #5 on: Tuesday, August 15, 2023, 14:25:23 »

Finder alignment should be as easy as-

Best to do it in daylight if you can see something far enough away from your garden/ observing site.

Point the sope at a tree/ church spire/ tv ariel in the distance, then tweak the little screws on mount barrel until the croshairs of the finder are centred on the same thing.

A moon filter makes a tremendous difference for viewing comfort- reducing the light through the eypiece to tolerable levels. If you need to stop it down more, some scope dust caps have a small removeable cap that opens up a little hole in the cap- this is to stop down the amount of light coming through when lunar observing- the little cap fits over the moulding next to it for safe keeping.
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The Artist Formerly Known as Audrey

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« Reply #6 on: Tuesday, August 15, 2023, 14:41:51 »

Something I could get into but donít know where to start.
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4D
Or not 4D that is the question

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« Reply #7 on: Tuesday, August 15, 2023, 14:55:14 »

Gotta start somewhere Aud. I just started watching YouTube videos, Astro Biscuit is quite good to watch, he seems a character.
I have a skywatcher 200p, seems to get approval as a very good starter scope.
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Jimmy StoppedMoaning

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« Reply #8 on: Tuesday, August 15, 2023, 14:57:44 »

Where did you purchase from and how much did it cost🤔
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4D
Or not 4D that is the question

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« Reply #9 on: Tuesday, August 15, 2023, 15:04:54 »

You my wife?  Cheesy

Bought 2nd hand for 200 notes, including extra lenses. About 500 new.
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Jimmy StoppedMoaning

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« Reply #10 on: Tuesday, August 15, 2023, 15:08:19 »

She did ask me to probe a little😀
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4D
Or not 4D that is the question

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« Reply #11 on: Tuesday, August 15, 2023, 15:09:49 »

Space probe?  Yay
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fuzzy

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« Reply #12 on: Tuesday, August 15, 2023, 15:13:57 »

Was that probing Uranus?
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Jimmy StoppedMoaning

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« Reply #13 on: Tuesday, August 15, 2023, 15:15:31 »

 Clap Clap
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Wobbly Bob

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« Reply #14 on: Tuesday, August 15, 2023, 16:46:45 »

Space Cadet 4D, welcome to the ranks.  Smiley
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