Scope for this mount?

[mypetcactus]

I am thinking to sav up for an HEQ5 mount. I have a Skywatcher 150p dob, which is 1200 focal length. The OTA weighs 15 lbs, and can acheive prime focus with no mods/barlows. It is an f/8. Now, would it be usable on a heq5? Is it too long? And, will it be ok as an f/8? Ive gotten some nice shots untracked, which i like. Plus, I am not looking to sell my work or put it out anywhere professinally. I want it just for me. Im confident I can get some neat shots with it. What are your guys opinions?

[rickwayne]

Welcome! The classic advice is to minimize your challenges when first starting astrophotography, since there is an irreducible minimum challenge level that's fairly daunting to most folks.

A small fast widefield refractor (e.g. 80mm, f/6 or better) is the easiest to mount and most trouble-free optical tube available. You want light weight and physically not too long to reduce the moment arm in order to reduce tracking challenges. Fast means that you can go with shorter exposures without running into trailing. Plenty of people succeed with longer, slower scopes, but quite a few of them express the wish that they'd started with something easier.

The rule of thumb for astrophotography is to run a mount at about 50% of its rated capacity. You're treading on that for an HEQ5 even without including a camera, or anything to guide with.

All that said, the other big rule is to spend till it hurts on mount, and accept whatever you can afford to put on it. If switching to an easier-to-learn scope would mean you dial back on the mount, you're better off either going with the optical tube assembly you already have, or mounting a camera and lens on it first and leaving the telescope for later.

[alacant]

14 hours ago, mypetcactus said:

And, will it be ok as an f/8? Ive gotten some nice shots untracked, which i like

Hi

Perfect. Guided on an eq6 using an oag, we use our Bresser 6" f8 for galaxies. It gets you away from the tiny-grey-fuzzy-patch-in-a-sea-of-nothing type images of shorter telescopes. Galaxies look like galaxies. The purity of the images is first rate; the light passes through no glass on its way to the camera as there is no coma to correct, even over aps-c. 

As you've already shown that it produces good images un-guided, be prepared for a nice surprise when you guide longer exposures. I'm sure that with good balance, the heq5 should guide it well.

Cheers

Edited February 1, 2021 by alacant

[mypetcactus]

19 hours ago, rickwayne said:

Welcome! The classic advice is to minimize your challenges when first starting astrophotography, since there is an irreducible minimum challenge level that's fairly daunting to most folks.

A small fast widefield refractor (e.g. 80mm, f/6 or better) is the easiest to mount and most trouble-free optical tube available. You want light weight and physically not too long to reduce the moment arm in order to reduce tracking challenges. Fast means that you can go with shorter exposures without running into trailing. Plenty of people succeed with longer, slower scopes, but quite a few of them express the wish that they'd started with something easier.

The rule of thumb for astrophotography is to run a mount at about 50% of its rated capacity. You're treading on that for an HEQ5 even without including a camera, or anything to guide with.

All that said, the other big rule is to spend till it hurts on mount, and accept whatever you can afford to put on it. If switching to an easier-to-learn scope would mean you dial back on the mount, you're better off either going with the optical tube assembly you already have, or mounting a camera and lens on it first and leaving the telescope for later.

Ok so, my dslr is 1lb, so 16lb alltogether on max 30lbs. It it fine if i do put that on a heq5? Or eq6r? I am young, so i cant get a job and refractors are very expensive. If anything i can use the heq5 with just a dslr. I know it will make problems possible, but can i do fine tracking?

[mypetcactus]

10 hours ago, alacant said:

Hi

Perfect. Guided on an eq6 using an oag, we use our Bresser 6" f8 for galaxies. It gets you away from the tiny-grey-fuzzy-patch-in-a-sea-of-nothing type images of shorter telescopes. Galaxies look like galaxies. The purity of the images is first rate; the light passes through no glass on its way to the camera as there is no coma to correct, even over aps-c. 

As you've already shown that it produces good images un-guided, be prepared for a nice surprise when you guide longer exposures. I'm sure that with good balance, the heq5 should guide it well.

Cheers

So 16 lbs on a he5 will do just fine? Since im not guiding, how long do you think my max exposures can be? Thanks, many people say it wouldnt work, but the AP community has a hivemind lol. 

[alacant]

You're on a budget, right?

The main advantage your telescope has is that it does not need any further correction. Any affordable refractor is going to need a corrrector; more expense.

The length of time you can track depends upon how well your mount is polar aligned. Maybe you could tease 60 seconds out of it but for best results at 1200mm, guiding would be recommended. But it sounds as if you're doing OK as it is. 

The heq5 will be fine. The usual advice is to get the heaviest mount capacity you possibly can, so there is always going to be someone who will advise you to get the eq6. Or eq8;)

Cheers