Need help choosing Newt for AP

[AstroMuni]

Hi, I have some experience of doing AP with my Astromaster 130, ASI224mc/ASI533mc on HEQ5Pro. I have purchased the Baader MPCC Coma corrector and that should be arriving this week. The weak link is the Astromaster hence wish to upgrade.

I DONT have an obsy so end up carrying the equipment in and out of the house. I have limited time to image due to work, lack of obsy and Clouds, hence need to make best use of the moments I get for imaging.  So after a lot of reading (and getting confused) I believe I need to look at 6inch aperture. Anything larger would make it too heavy for the HEQ5. I have deliberately stayed away from refractors at this point in time.

The choice that I have narrowed down to is between:

- SW 150pds vs TS Photon 6 f5 (Chris from FLO tells me that TS has a better focuser)

- SW Quattro 6 f4 vs Stellalyra 6 f4 (I would love to go for these but the question is what are the chances that it will lose collimation when I carry it in and out)

I have restricted myself to look at products available on FLO at the moment, but open to suggestions.

Need your advice please.

 

Edited October 19, 2022 by AstroMuni

[NGC 1502]

All the best in your endeavours…..however-

Perhaps your enquiry would be better in the “getting started with imaging” section😊

[AstroMuni]

4 hours ago, NGC 1502 said:

All the best in your endeavours…..however-

Perhaps your enquiry would be better in the “getting started with imaging” section😊

As this was equipment related I posted it here...but seeing the lack of response I guess it would be better suited for the imaging section 😞

@admin if you think this is more appropriate for Imaging section could you move it please?

Edited October 20, 2022 by AstroMuni

[wimvb]

The 150PDS and its little brother are both good scopes for AP. The 130PDS has its own thread in the beginner’s imaging section. F/5 scopes are less fussy about perfect collimation and focus than F/4, so have a slight advantage in the field. The 150PDS is larger/heavier than the 130PDS and more sensitive to wind. If you save a few £ on the scope, you can use that to eg upgrade the mount with a belt. This will improve tracking accuracy.

[AstroMuni]

35 minutes ago, wimvb said:

If you save a few £ on the scope, you can use that to eg upgrade the mount with a belt.

So are you suggesting I would get more bang for the buck if I opt for the 130PDS instead, and upgrade the belt etc.?

[Elp]

It's much wider than you're looking for but if imaging time is an issue the Samyang 135mm works very well. I would also suggest a refractor if you want minimal fuss setting up. The 130pds is an excellent scope, very sharp, just takes a few mods to get it working well if you take a look at the main thread on this scope.

[AstroMuni]

49 minutes ago, Elp said:

It's much wider than you're looking for

Sorry, didnt understand that bit. I am using a 130/650 scope at the moment and perfectly happy with the FOV with the ASI533. The Samyang is definitely on the cards but thats a separate parallel track 🙂 One of the reasons I want to stay with the reflectors is wider aperture and an ability to go down the track of doing IR photography. JWST has inspired me in that direction.

Edited October 20, 2022 by AstroMuni

[Clarkey]

I would have to echo @wimvb comments regarding the f4 scopes - unless you want to spend extra for a 'decent' one. I got the TS 6" for imaging and the MPCC I had was not up to the job, so I had to buy the aplanatic CC. (I know the specs say the MPCC should be OK - but reality showed otherwise). Also, the focuser sag made collimation very difficult - so I replaced with a Baader ST. After all the expense I was still not overly impressed as I had major problems with internal reflections from filters. After a couple of sessions I binned it and sold the extra's. Collimation was also tricky to get spot on. Overall, I wasted about £800. 

F5 is much more forgiving.

What is wrong with a widefield refractor? Simple, reliable and very portable?

Edited October 20, 2022 by Clarkey

[wimvb]

2 hours ago, AstroMuni said:

So are you suggesting I would get more bang for the buck if I opt for the 130PDS instead, and upgrade the belt etc.?

In AP the mount is probably more important than the optics (but of course, garbage in, garbage out). It pays off to spend some money on improving the mount. Since the mount is such an important part of any AP setup, it should not be overlooked in an upgrade.

I have the 150PDS, not the 130PDS or the 6” photon. But it seems to me that if shown images taken with either, you’d have a hard time figuring out which scope was used, apart from the slightly different fov due to the difference in focal length. The main issue people have with the 130PDS, is that the focuser draw tube may protrude too far into the light path, resulting in diffraction artefacts around bright stars. I have no idea if the 6” photon has similar issues, but it’s worth investigating, imo. The price difference between the scopes isn’t that much, unless you want a carbon tube.

[AstroMuni]

3 hours ago, Clarkey said:

What is wrong with a widefield refractor? Simple, reliable and very portable?

Just the aperture ....esp since I would like to try IR imaging

[AstroMuni]

1 hour ago, wimvb said:

The main issue people have with the 130PDS, is that the focuser draw tube may protrude too far into the light path, resulting in diffraction artefacts around bright stars.

And the 150pds doesnt have that issue?

[Elp]

5 hours ago, AstroMuni said:

Sorry, didnt understand that bit.

The Samyang 135mm is a wide lens compared to a typical telescope so you'll get much more in the FOV. It runs well at one stop down from F2, so it'll be faster than what you're used to. Only issue is obviously loss of resolution.

If you're looking to do the type of IR imaging I am imagining you want to try (IE not planetary), note, A. Most cameras are not very quantum efficient in the full IR wavelength (hence why some planetary cameras are advertised as Near Infra Red NIR), B. I had read somewhere to capture a similar signal compared to visible light in IR you have to expose for 25 times as long in comparison and C. Moisture in the atmosphere doesn't play well with allowing IR photons through (hence why IR scopes are high altitude or in space). It'd be interesting to try though and works quite well with planets.

[AstroMuni]

5 minutes ago, Elp said:

The Samyang 135mm is a wide lens compared to a typical telescope so you'll get much more in the FOV. It runs well at one stop down from F2, so it'll be faster than what you're used to. Only issue is obviously loss of resolution.

If you're looking to do the type of IR imaging I am imagining you want to try (IE not planetary), note, A. Most cameras are not very quantum efficient in the full IR wavelength (hence why some planetary cameras are advertised as Near Infra Red NIR), B. I had read somewhere to capture a similar signal compared to visible light in IR you have to expose for 25 times as long in comparison and C. Moisture in the atmosphere doesn't play well with allowing IR photons through (hence why IR scopes are high altitude or in space). It'd be interesting to try though and works quite well with planets.

This is what got me interested. I am more into DSOs at the moment...https://satakagi.github.io/IR-imaging-of-galaxies-under-light-pollution/.

[Elp]

Definitely worth looking at, I saw that webpage before I bought the filters so worth exploring indeed.

[ONIKKINEN]

For better options than the PDS or photon there is the TS ONTC 6" f/4: https://www.teleskop-express.de/shop/product_info.php/info/p12848_TS-Optics-150-mm-f-4-ONTC-Newtonian-Telescope-with-2--Focuser.html

Since the tube is rigid and well put together you skirt around a major part of collimation troubles.

Also the UNC 6"f/5: https://www.teleskop-express.de/shop/product_info.php/info/p13462_TS-Optics-6--f-5-UNC-Newtonian-Telescope-with-Carbon-Tube.html

Both are pricier than the 150PDS, but the price is in the right places. Astrophotography with a newtonian is viewed as troublesome mostly because most of the cheap newtonians are specced for visual, so have lacking mechanical rigidity and only ok focusers.

[wimvb]

3 hours ago, AstroMuni said:

And the 150pds doesnt have that issue?

Not so much that I was tempted to grab the hacksaw

https://www.astrobin.com/331604/F/?nc=&nce=