Spend my money...

[Richard N]

I have an ST80 and an ETX90 OTA both of which I mostly use on an AZGTi mount.

What OTA would you suggest that would make a significant improvement? Explain why.

Must be light enough to use on the current mount.

I am only interested in visual astronomy. Bortle 5 site.

I don't have any specific observing interests but DSOs are hard work from my site so I tend to look at other stuff.

Budget £500.

 

PS I did try a 130/900 Newtonian on the mount but it wasn't stable enough (for me).

Edited July 15, 2023 by Richard N

[NGC 1502]

The 2 scopes you already have complement each other nicely.  ST80 for low power wide field, ETX90 for medium to higher powers.

If the 130/900 Newtonian was not stable on your current mount your choices are very limited.  Perhaps a short focal length 114/500 Newtonian?  That would give more aperture than you already have, and still provide low power wide field, higher power, and be in budget.

All the best in your choices😊

Ed.

 

Edited July 15, 2023 by NGC 1502
Extra info

[Elp]

What do you want to improve?

[Richard N]

3 minutes ago, Elp said:

What do you want to improve?

Good question. Of the two scopes that I have, the ST80 seems to have the poorer optics. But then again they both have relatively small apertures.

[Elp]

I've often wondered if I get a larger aperture will it improve my view if this is what you're getting at. And I don't think it will. An option for you is a C6 OTA which will give you additional focal length plus aperture. It brightened up very very slightly an already faint for me M13 averted view, but it was still very very faint and invisible if looking at it directly coming from a 130pds. The C6 is small and light enough to work on the azgti, it can however struggle to point and track at that focal length, especially if you use a Barlow.

To improve your optics, think an apo refractor is an option if you can find one maybe used within your budget, but the question will remain whether for visual it will be an improvement from what you have already. I know for me coming from a low budget acro to the apo was a night and day difference both visually and photographically, the latter of which is much more testing of the optics, and it's the clearest scope I've used, granted I haven't used many at all but have owned acro, apo, newtonian and sct.

[Richard N]

It could be that I would gain more by buying a dielectric diagonal and a couple of good quality eyepieces? Currently using BST types.

[The60mmKid]

I think the mount is what makes this difficult. With a stated 5KG capacity, I wouldn't want to put more than 3KG on it. I have no experience with the AZGTI, but based on those numbers, I might go for this: https://www.altairastro.com/starwave-ascent-80ed-f7-refractor-telescope-geared-focuser-469-p.asp It'll be a reliable performer, meaning that it doesn't require much thermal acclimation and will provide good images even when the seeing is iffy. It's also versatile... sharper than the ST80, and the maximum FOV is wider than the ETX 90's. So, it sort of combines the strengths of the two scopes that you already own, which I'd recommend selling if you buy this one.

Is goto a necessity for you? If not, would you consider replacing the mount, which would expand your options for OTAs (e.g., enabling you to use a 4" refractor), and/or buying a dobsonian?

[Cosmic Geoff]

Buying fancy diagonals will give a marginal, perhaps un-noticeable gain in performance over stock types.  If you pay more, the gain is mainly in better construction, longer coating life etc.

If you want more performance for visual astronomy on a budget of £500, the obvious answer is to buy a 8" or 10" Dobsonian.

[Elp]

17 minutes ago, Richard N said:

Currently using BST types.

These are quite decent already. More premium you'll only gain in FOV if you go that way, edge sharpness, CA control (dictated more by the scope) and contrast. The differences become very subjective to the individual.

Regarding stability on the azgti you can mitigate this somewhat by using the threaded hole and attaching a DIY counterweight and bar, some people even use this hole to attach a second ota for dual use.

[Gfamily]

Are you a member of an Astro Society (Macc Astro is highly regarded and near you)? If they have observing sessions, you may have a chance to look through other people's scopes and see what they're using.

Alternatively, we're looking towards the autumn Star Party season, so if you can free up a weekend, these can be good for meeting a variety of people and see a variety of scopes.  We're aiming to be at the Astrocamp Star Party near Crickhowell in September, bookings open next weekend (google Awesome Astrocamp) 

Personally, I have a 72mm refractor and a 127 Maksutov, both of which work on my AZ GTi - the refractor has a good wide angle field of view and GOTOs are always successful - for the Mak, I sometimes find that GOTOs can be a little off - so I sometimes have to hunt around to confirm the target in the FOV. I think it's the weight is a little more than the mount likes - but once the target is found it works OK.  I usually goto a bright star nearby, them SYNC, and then it's only a short hop to the target. 

 

[Richard N]

1 minute ago, Gfamily said:

Are you a member of an Astro Society (Macc Astro is highly regarded and near you)? If they have observing sessions, you may have a chance to look through other people's scopes and see what they're using.

I am a Macc Astro member. That's a good suggestion. I have looked through a few scopes but most members seem to be imagers.

[Roy Challen]

1 hour ago, Richard N said:

 

I am only interested in visual astronomy. Bortle 5 site.

I don't have any specific observing interests but DSOs are hard work from my site so I tend to look at other stuff.

Budget £500.

'Other stuff' being planets, moon, double stars? In that case, it will be difficult to better the ETX, imo. My FS60-CB certainly isn't better than my Skymax 90 for those targets, but it is a great wide field scope and very portable, but then again so is the ST80. They complement each other very well.

An ED80 would be a decent upgrade over the ST80, and may even beat the little mak if the seeing is good.

[DirkSteele]

If by better you mean goes deeper, i.e makes DSOs brighter, combined with the weight limit of the mount (5kg though I would t push it past 4 really though short and stubby scopes are easier to mount than long ones), I would consider a 5” Mak which is 3.2kg and about £300 for the OTA. Only issue is the longer focal length giving narrower fields but you have your 80mm Frac for that. Alternatively, you could consider a heritage Dobsonian, either the 130 or 150 and just remove from the supplier table top mount and use yours. I believe I am correct in assuming they can be easily mounted on a vixen dovetail compatible mount. Just make a shroud for the top piece to keep out stray light.

 

And as both are well within budget, use the difference to buy a better tripod which will improve stability.

Edited July 15, 2023 by DirkSteele
Add extra suggestion

[The60mmKid]

If you're open to non-goto, I think the suggestions to simply add an ~8-10" dob are great. You could buy one of those and keep the setup you currently have, selling off the mak if you decide later that it's superfluous. The ST-80 is a wide-field scope, so it would remain relevant if you added a dob.

This way, you don't have to find something that the AZGTI can handle... And an 8-10" dob will show more of everything than an OTA that the AZGTI can handle.

[AstroNebulee]

5 hours ago, DirkSteele said:

If by better you mean goes deeper, i.e makes DSOs brighter, combined with the weight limit of the mount (5kg though I would t push it past 4 really though short and stubby scopes are easier to mount than long ones), I would consider a 5” Mak which is 3.2kg and about £300 for the OTA. Only issue is the longer focal length giving narrower fields but you have your 80mm Frac for that. Alternatively, you could consider a heritage Dobsonian, either the 130 or 150 and just remove from the supplier table top mount and use yours. I believe I am correct in assuming they can be easily mounted on a vixen dovetail compatible mount. Just make a shroud for the top piece to keep out stray light.

 

And as both are well within budget, use the difference to buy a better tripod which will improve stability.

Indeed as you say about the heritage 130 or 150 scopes. 

As Steve @bomberbaz here shows as he's mounted his heritage 130 on an AzGti mount and made a fine job of it. I know Steve's set up is for imaging but easily the same for visual. So a heritage 150 too is a nice scope for the AzGti. The AzGti can put up a lot with weight as long as its balanced well in az or eq with a counterweight. 

Lee 

Edited July 15, 2023 by AstroNebulee

[Ratlet]

I've found a 130pds works well on an azgti, so the heritage 130p will work well.  I think it's the shorter focal length reduces the movement arm.

I have found though that the tripod makes a huge difference in stability, I'd it's the cheap aluminium tripod I'd consider upgrading it to the 1.75" steel tripod.  Makes a huge difference in stability although it is much bigger and heavier than the aluminium

[fwm891]

10 minutes ago, Ratlet said:

I've found a 130pds works well on an azgti, so the heritage 130p will work well.  I think it's the shorter focal length reduces the movement arm.

I have found though that the tripod makes a huge difference in stability, I'd it's the cheap aluminium tripod I'd consider upgrading it to the 1.75" steel tripod.  Makes a huge difference in stability although it is much bigger and heavier than the aluminium

I use a surveyors tripod much much cheaper than an astro tripod. just change the anchor bolt to 3/8th UNC or Whit thread.  https://smithsurveyingequipment.co.uk/product-category/surveying-accessories/tripods/

No affiliation etc... just bought a tripod.

[AstroNebulee]

4 hours ago, Ratlet said:

I've found a 130pds works well on an azgti, so the heritage 130p will work well.  I think it's the shorter focal length reduces the movement arm.

I have found though that the tripod makes a huge difference in stability, I'd it's the cheap aluminium tripod I'd consider upgrading it to the 1.75" steel tripod.  Makes a huge difference in stability although it is much bigger and heavier than the aluminium

I agree too. I upgraded from the black star adventurer tripod to the sw 1.75inch tripod and my what a difference for my overweight set up and totally solid now. The tripod a little bit heftier but manageable. So @Richard N for your money maybe consider the heritage 130 or 150 mounted to your AzGti and the upgraded 1.75inch tripod. Plus as you won't have cameras hanging off the focuser you'd have no issues with it, the ptfe tape mod will tighten it up if needed. 

Lee 

Edited July 15, 2023 by AstroNebulee

[LukeSkywatcher]

4 hours ago, AstroNebulee said:

Indeed as you say about the heritage 130 or 150 scopes. 

As Steve @bomberbaz here shows as he's mounted his heritage 130 on an AzGti mount and made a fine job of it. I know Steve's set up is for imaging but easily the same for visual. So a heritage 150 too is a nice scope for the AzGti. The AzGti can put up a lot with weight as long as its balanced well in az or via a counterweight. 

Lee 

You can't go far wrong with Skywatcher Heritage 130P. It's still probably my favourite scope.

[bomberbaz]

12 minutes ago, AstroNebulee said:

I agree too. I upgraded from the black star adventurer tripod to the sw 1.75inch tripod and my what a difference for my overweight set up and totally solid now. The tripod a little bit heftier but manageable. So @Richard N for your money maybe consider the heritage 130 or 150 mounted to your AzGti and the upgraded 1.75inch tripod. Plus as you won't have cameras hanging off the focuser you'd have no issues with it, the ptfe tape mod will tighten it up if needed. 

Lee 

 

If you read my Heritage 130p mod thread there is a better focuser mod than ptfe tape. It simply involved 2 small pieces of loop velcro tape and gives a far better & more permanent mod to stiffen up the focuser. 

[bomberbaz]

I should have also given my view on the 150p. I think it is a step too far for the AZ Gti. Not so much the weight but the length will introduce too much flex into the system although I could be wrong but that's my opinion on the matter.

[LukeSkywatcher]

1 minute ago, bomberbaz said:

If you read my Heritage 130p mod thread there is a better focuser mod than ptfe tape. It simply involved 2 small pieces of loop velcro tape and gives a far better & more permanent mod to stiffen up the focuser. 

The focuser on the SWH 130P is its only fault. I found a couple of layers of electrical tape a great fix. It will probably need replacing often, so I may try the sticky velcro loop. 

[AstroNebulee]

3 minutes ago, bomberbaz said:

If you read my Heritage 130p mod thread there is a better focuser mod than ptfe tape. It simply involved 2 small pieces of loop velcro tape and gives a far better & more permanent mod to stiffen up the focuser. 

It's a great mod and very simple and longer lasting as you say Steve. I like your 130p set up a lot. Damm there's another scope (or 150p) I'd like for my AzGti's 😂. 

Lee 

[Jules Tohpipi]

8 hours ago, Richard N said:

I have an ST80 and an ETX90 OTA both of which I mostly use on an AZGTi mount.

What OTA would you suggest that would make a significant improvement? Explain why.

Must be light enough to use on the current mount.

I am only interested in visual astronomy. Bortle 5 site.

I don't have any specific observing interests but DSOs are hard work from my site so I tend to look at other stuff.

Budget £500.

 

PS I did try a 130/900 Newtonian on the mount but it wasn't stable enough (for me).

 

I have the SW ST102 and 127 Mak on an AZ-GTi. So same kind of set-up as yours but with a bit more aperture. How that actually compares through the eyepiece to yours I don't know.

From direct experience, I can say two things make a big difference compared the above - that are within the £500 budget. 

1. A manual 8" dob - lots more light and better resolution for visual

or

2. Drop a ZWO ASI585MC camera directly into your diagonal (exactly the same as dropping an eyepiece in) and connect it via USB to a laptop. The free SharpCap software will show the live image on the screen and build a live stack of, say, 5 second exposures. To clarify, my first ever go at trying this, I had the below live-view stack of M13 on my screen in under three minutes using my ST102 on the AZ-GTi in Alt-Az mode. It represents the absolute least of what's possible. EEVA is very suited to visual astronomers because it's a technique that gets results quickly (image develops in front of your eyes in a few minutes rather than hours) yet shows far more than you would ever see even through an 8" dob. Check out the EEVA forums here if curious.

 

 

 

 

Edited July 15, 2023 by Jules Tohpipi

[ScouseSpaceCadet]

Mount a Heritage 130P on the AZGTi on top of a 1.75" steel tripod. The AZGTI does come in a package with a  130PS but unfortunately one cannot buy these telescopes new separately from the mount. However the Heritage 130P is similarly specced and will work fine. Put the money saved away in the astro kitty for nicer kit in the future.