cmanley134

7 hours ago, alacant said:

Hi
I wonder about those. The 130pds has -at least- a 500mm dew shield already. It maybe the climate here, but I've never had dew on any Newtonian. 1º or 2º. Refractors, yes.
Just curious.
Cheers

Primarily for light pollution purposes for me. I get tons of stray light from neighbors and would have lots of nasty reflections if not for a good dew shield.

Has anyone 3D-printed a dew shield for their scope? I have one of the floppy adjustable ones and I'd prefer something a little more secure with a consistent/repeatable fit. I don't have any 3D printing equipment myself but if anyone has the file I know someone who could do the printing for me. Thanks!

First image with the modified drawtube - this does have BXT stellar correction, but the change has definitely helped. Stars are nice and round and I've even seen a ~10% decrease in FWHM. Also tried a narrowband/broadband mix here which I quite like. Next up, secondary spider! I've received my CNC spider from Backyard Universe and just need to get it installed.

On 19/01/2024 at 17:50, 8472 said:

Not really, a hacksaw should do it and yes, you don't want to leave any burrs to lacerate your or any future owner's hands.

Upon re-assembly, I covered any exposed metal with black self adhesive flocking material.

Just be wary of how much of the drawtube you remove.

Take too much off and the tube will come off the rollers in the focuser when you wind it fully out.

Additionally, I shifted the primary up the OTA, so I wouldn't have to saw too much of the drawtube off.

Good luck!

1 hour ago, sagramore said:

Can confirm - I shifted my primary up the tube and didn't modify the focus tube at all. Protrusion is negligible now and the mod is reversible. Although I would guess a combination of both, as suggested by 8472, is in fact the optimum final result.

Thanks all - ended up taking 13mm off of the end, based on the difference between my focus point and the point at which the tube protrusion was no longer visible. Just need to finish painting the end and reinstall. I'm not a visual guy but I did see some reports that this mod can cause the tube to fall out when fully extended - I still have another 10+ mm on the end before the flat spot where the focuser makes contact starts, so I think I should be okay. 

6 hours ago, 8472 said:

No, you can completely remove the drawtube from the focuser, from your picture.

Great, thanks! Any special tools needed, or just hacksaw and sand down any rough edges?

Okay, here's another maybe dumb question - I'm using a reducing corrector and want to chop my drawtube. Looking through a Cheshire it seems that I need to take maybe 12-13mm off of the end to completely eliminate the protrusion. I really would prefer to remove the drawtube so I can clamp it and make the cut separately rather than removing the entire focuser housing/assembly. Once I get to the point shown here:

Will the focus stop prevent me from removing the drawtube? If so, is there a way around that? The focuser is nice and square right now thanks to the previous owner and I'm quite leery of doing anything that will mess with that, given my relative inexperience. Thanks!

23 hours ago, Whistlin Bob said:

I'm afraid I can't answer your question, but I do wonder how necessary they are. I wasn't happy with the appearance of the stars on my 150 Quattro, but used some calipers to ensure the vanes were precisely adjusted. They've stayed true for about ten months so far.

Necessary, probably not - that being said, it seems like the thicker vanes produce a nicer spike and that the extra stiffness will result in more consistent collimation. As I see it the main differences between this scope and similar higher end offerings are the focuser, mirror holders/cells and the tube material - the mirrors themselves are already excellent. My focuser is okay for my current image train, and if I get the nicer secondary spider sorted, there would be even less of a difference between this scope and any premium option I might consider upgrading to.

Question regarding replacement of the secondary spider - are there any U.S. made options? Backyard Universe does the CNC machined spider but it's quite pricy and ships from overseas.

Finally capped off my efforts on M33 - finished with just over 13 hours of data that took a remarkable 16 hours (wow!) to stack in PI on my M1 Mac. That being said, the 2x drizzle and superior rejection/normalization process was worth it over my usual routine in Siril. Really pleased with how this came out: 

Question for those who are using a primary mirror mask - I've had a U.S. based seller (Spencer 3D on eBay) 3D-print one and he said he used PETG that is not a matte finish. Will that be an issue as far as causing internal reflections? Because I can always paint it before install.

Finally had a chance to do an extended integration on something - about 6 hours of 120s subs from my Bortle 6 neighborhood (2600MC, L-Pro). I may add more to this but I am really enjoying this little scope.

After my initial tests with the Stellalyra/GSO corrector I wasn't satisfied with the stars - picked up a Sharpstar 0.95x (TS Maxfield clone) and there is a massive improvement. FWHM is about 30% lower and the corners are excellent on my 2600MC Pro. Only managed to get 9x2 minute test exposures before the clouds rolled in but for 18 minutes I think this is neat.

Well, first light was a success - got everything set up and captured 45 x 120s on M45 as my testing target. Lots of things went great! No light leaks, focuser had plenty of tension to hold the image train and I reached and maintained focus easily. Data was clean and easy to process. Star shapes need some fine tuning but this thing is awesome for the money. 

Spent some time messing with the new scope - got that third screw tapped with a cheap tap and die set off of Amazon and got everything put together to see if I could reach focus.

It does seem like I need to have the focuser racked almost all the way out to focus on the trees across the street maybe 100ft away. I've had the experience with my refractors that the focus point is actually closer in compared to what I get when I try during the day, hopefully that is the case here. Do others with the GSO corrector find that their focuser is nearly fully extended?

The good news is that the third screw is a major improvement - no more play in the image train. Looking forward to first light, if the clouds ever let up.

1 hour ago, edarter said:

Thats a very tidy cap you have over the mirror end, where did you source that from?

I was actually lucky enough to receive them with the scope courtesy of the previous owner, but I found them here: https://www.optechusa.com/products/hood-hat?variant=44409884082471. U.S. company so not sure if they ship overseas, but pricing is reasonable. I believe this is the second largest size (XXX-L)

Tried a test-fit with the corrector and ~75mm backspacing - with the camera rotated vertically where it has the most leverage, the focuser seems to be holding the weight. Definitely needs the third thumb screw though, as I can feel some play currently. I picked up a tap and die set so I'll be adding that this weekend.

1 hour ago, alacant said:

JTOL and I'm hoping that YMMV...

Have you checked to see if the focuser is capable of holding the camera/cc/fw assembly at the required distance? Even with a quality 2-1/2" r&p, we gave up with a similar specified ES. Here we are at 80mm with a DSLR at the focal plane:

That's my task for today - as you may have seen in my previous post the corrector is filthy! Needs a good cleaning before it goes anywhere near my filters and/or camera sensor.

1 hour ago, alacant said:

We can't advise because we don't know the diameter of your spacers. m48 gives you the option of clamping anywhere along the length. Unfortunately, zwo supply only m42.

The main problem with the gso is retaining stability and balance with the focal plane so far from the tube. 

Hmm, I guess I can relocate the filter drawer to attach directly to the corrector - it's moving the filter further away from the sensor but I doubt that'll be an issue. Would solve this particular problem. And we'll see how it goes! I agree that the 75mm is a lot - I may pick up an MPCC at some point.

20 minutes ago, alacant said:

Hi

Yes. Indeed... Nothing.

Fortunately, it would never be employed in such configuration.

The GSO has m48 threads, so as long as you have allowed for any adapter 48 to 42, the 75mm would be a good place to begin the positioning trials. IIRC, over aps-c, you'll probably find the best correction is however nearer 80mm; there is usually a 5mm m48 to m42 adapter supplied already fitted.

Cheers and HTH

Thanks for the response! So, if I am understanding correctly, I am going to simply align the top of the corrector with the top of the focuser and clamp it in that position? So the entire corrector is inserted into the focuser tube and the spacers that comprise my backfocus are exposed.

Hi all - proud new 130P-DS owner here (yay!) and happy to join the thread. I'm sure this has been answered at some point, but I'm attempting to use the Stellalyra (rebranded GSO) corrector and it seems that in its most basic configuration, the corrector has nothing to keep it from falling down into the tube apart from the screws on the focuser. With the 2" visual adapter or a t-ring attached there is a lip/flange that holds it in the right position, but my planned image train was ZWO ASI 2600MC > 21mm filter drawer > 21mm spacer > 16.5mm spacer > corrector to achieve the quoted backfocus of ~75mm. Am I missing a piece here? Thanks in advance for any assistance!