150PDS and APS-C? - Forums

Topic starter

Jan 24, 2022

I've been thinking of giving a newtonian a try for imaging and the Explore 150PDS has come up as an option, 6" f/5. I've seen some images taken with APS-C DSLR's but have not been able to get much info on this scope. I have the ASI2600MM Pro and think it should pair well. I've considered either the 1.0x or 0.95x TS coma correctors.

Anybody have experience to share? Any things you'd change about the scope? Maybe focuser?

Thank you!

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Scott

Jan 24, 2022

I have the 130PDS, which is the 5" F5 version of the scope. I use it with a 2600MM as well, paired with the Nexus coma corrector, which is 0.75x. The combination works quite well, with sharp stars all the way to the corners. I did swap out the focuser, replacing the stock unit with the one taken from my 12" Quattro (which was swapped out for a Moonlite, so I had it on hand). The Quattro focuser is a bit more robust, and with the 7 slot 2" filter wheel the 2600MM is over 4lbs. I found the 130PDS easy to collimate and it holds well, the 150 should be very similar. Vignetting was better than I expected, and easily corrected with flats. I really like the 130, for the money it's a great little imaging scope rivaling APO's costing several times as much. Here is an image shot with the 130PDS/2600MM:

https://www.astrobin.com/lwdb6i/0/

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jewzaam

Topic starter

Jan 24, 2022

Thanks for the info Scott! Any challenges on the focuser change? I've seen some scopes (though I don't recall for these) having non-standard holes. Not the end of the world but it's good to hear things are a "drop in replacement". Great M31 image! I'll look into the coma corrector you reference as well though it is then f/3.75. Any thoughts/risks/issues on going faster? I have no experience with a Newtonian for imaging except a wild experiment mounting an Orion XT8 on my EQ6-R Pro cause.. why not!

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Scott

Jan 24, 2022

The focuser swap was fairly easy for me as it was one SW focuser swapped for another. I used the base from the stock 130PDS focuser, and attached the mechanics of the Quattro focuser to that base. Swapping to a different brand of focuser might be more difficult.

As for the Nexus CC, I was going for a fast, wide field scope, so the 0.75x CC fit the bill. Collimation and focus are more critical the faster you go, but I had no issues getting it right at f3.75.

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Tristan Campbell

Jan 24, 2022 · Edited: Jan 24, 2022

I recently got a 150PDS as a second scope mostly to use in less than ideal conditions - sometimes the wind is an issue from my exposed location so a smaller scope is easier for the mount. Overall I'm liking the scope but so far I've been using my 1600MM so a smaller sensor. I have used the 2600MC on it but the stars are not as good towards the edge. However I'm pretty certain this is either my collimation or a spacing issues that I've not managed to quite sort yet.

The scope ideally does need modifying a bit though. I've particularly had issues with dew and weird internal reflections. For the dew I've added a rear fan and made a dew shield. Still working on reflections some of which seem to be coming through the rear of the tube. I don't want to completely seal the rear as I've seen people do with this scope as I want to keep the fan so I've recently blacked out the rear of the mirror cell. Love the idea of a reducer but I'm not going to risk it until I can much improve the stars on APSC.

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David Moore

Jan 24, 2022

I have the 130PDS and the 200PDS and image with the 2600MC. I find the focusser quite adequate and have fitted the ZWO digital focusser to both. I needed to fit a dew shield and heater band to stop the secondary misting up and I also fitted a fan and flocked them though I haven't noticed any difference with the flocking. Collimating is easy with an old Cheshire eyepiece. Stars are nice and round at F5 for both. The 130PDS is quite small and light to handle.

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jewzaam

Topic starter

Jan 24, 2022

Thank you! Regarding the adequate focuser, is it introducing some tilt or other issues? I've gotten commentary about one 150PDS user on AB having issues with the focuser. It's one of the areas on my current doublet that is frustrating me the most, tilt from focuser and field flattener, and I'm looking for a scope on which I'm happy to do the upgrades to make things better.

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David Moore

Jan 25, 2022

I suspect but not sure that the issue with the focusser may be for some at least the the tension between the running surfaces needs adjusting otherwise the camera can slip when pointing downwards especially if heavy. I have had no problems with my APS-C camera. However I did have tilt problems with my full frame Sony A7III. Full frame shows up tilt problems. What I like about the 130PDS is that it is very cheap for the diameter and an F5, collimation is easy and the results are good. It hasn't caused me any issues. I do have a high quality coma corrector with a long barrel which aligns well with the focusser tube. I did buy an F4 Newtonian and had so many complex tilt issues that I gave up and returned it which was a shame as it was carbon fibre and didn't need frequent focussing.

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jewzaam

Topic starter

Jan 25, 2022

I've been looking at TS-optics coma correctors, the 1.0x and 0.95x. Also maybe some time in the future if I feel a bit crazy the 0.75x Starizona corrector but need to learn closer to f/5 before pushing down to f/3.75 and pulling my hair out.

Mind sharing what coma corrector you're using that works well?

Thanks!!

Scott

Jan 25, 2022 · Edited: Jan 25, 2022

I use the SkyWatcher Quattro CC, which is an excellent 1.0 coma corrector. TS also sells a version of the same unit, optics by GPU. It's designed for F4 and F5:

https://www.skywatcherusa.com/products/sky-watcher-quattro-coma-corrector

TS version:

https://www.teleskop-express.de/shop/product_info.php/info/p6706_TS-Optics-NEWTON-Coma-Corrector-1-0x-TSGPU-Superflat---4-element---2--connection.html

David Moore

Jan 25, 2022

Not at all. Here is a link to the excellent firm I got it from. I have no connection with them apart from using them a lot. The part with knobs on unscrews as it is for a manual eyepiece which I admit puts the price up if not used. It is a 4 lens design and no doubt there are other ones that would do just as well. The rest of the assembly screws onto my ZWO ASI 2600MC APS-C camera with the provided spacers. I leave it on all the time so dust bunnies are not an issue though I don't have a filter wheel yet which might re-introduce them? I have made a short annular spacer ring out of a piece of plywood to fit over the coma corrector tube so that I can fully insert the whole assembly in to the focusser. otherwise I have to pull it out about 10mm which is no big deal but this upsets repeatable focussing with a digital focusser so repeatability is useful. It does not intrude inside the scope.
https://www.firstlightoptics.com/coma-correctors/explore-scientific-hr-coma-corrector.html

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