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Imaging with the 130pds


Russe

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On 24/04/2018 at 09:15, moise212 said:

I've one finished image too while others are in progress. I will replace this weekend the secondary mirror with a larger one and, perhaps, cut a bit off from from one side of the focuser.

Meanwhile, the finished image, in another thread and original.

https://stargazerslounge.com/topic/311677-m13-lrgb-with-130pds/

Clear skies!

M13-F588-2018-04-12-LRGB_p03_watermark.jpg

Wow, that's very impressive!

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M53 and NGC5053 first quick process, taken with the QHY168C at Gain 10, Offset 40, Temp = -10ºC, IDAS D1 but with white led streetlights beside :-(. Only 13x120s unguided subs.

Taken in Aranjuez 30km from Madrid downtown, so below the lightpollution mushroom.

Cheers.

M53_NGC5053_annotated.thumb.jpg.c541af64a7ac6a59ad259a04fa3439bc.jpg

Edited by Susaron
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Hi,

I feel slightly embarrassed posting my attempts here! :undecided:

A sort-of-test M51 image, with EOS 1000d (Modded) 1 hour 2 mins of subs, at ISO 800 120 sec each. 

Mounted on EQ5 with dual-axis motors, guiding using ST4 and PHD.

There's a bit of gradient caused (I think) by the flats not matching up to the data images, this was because a small piece of plastic loosened by the modding process fell onto the camera sensor when I rotated the scope back down from tracking M51. I had to remove the camera to get rid of it, so there is probably a slight angle error between flats and lights.

I'm quite pleased with the results, considering it was full moon, the collimation wasn't amazing, and a small galaxy is not what my setup is designed for.

John

M51.thumb.jpg.886969c894d1608410db0d81c25ffe8f.jpg

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Does anyone know where I can find a replacement primary mirror for this scope? Is it the exact same mirror as for the lower cost 130/650 ones?

I think I might overcleaned mine..

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This is an interesting question, specially for the big amount of 130PDS owners. My scope is 5 years old and there will be a moment in which due to pollution the coating will be degraded and therefore the mirror will need a replacement.

Try to ask FLO as they have a close contact with SW, also ask in Teleskop-Service in this page they have up to 150F4 mirrors but anything about the 130P.

Regards.

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Thanks, guys!

I can send it for a re-aluminization, but this will take a while. I'm not really happy wasting the clear nights so I'd take the fastest option. I found also mirrors >= 150mm, but no 130.

I have to perform some more tests before concluding the mirror is not good enough anymore.

If the mirror needs to be replaced, I might consider replacing the scope. At 750mm with the 0.9x reducing SW Coma Corrector, the 150PDS could be a better option for smaller targets and still within my AZ-EQ5 mount handling capabilities. Or a nicer carbon OTA.

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Hi,

I believe that the mirror is the same as the standard 130P, although there is another version (Which I happen to have as well) which came in a starter pack with an EQ2. Often marketed as the Explorer 130M, if i remember right. As far as I know, the P-DS has the primary mounted on the inside not the outside of the mounting rings on the end of the tube, giving a focus point further from the focuser (shortening primary-secondary separation while maintaining the same focal  length.

Those carbon OTAs look amazing, right? Especially the Orion Optics ones (not Orion as in Orion Telescopes and Binos) with orange tube rings and extractor fans! :D 

Apparently, the latest generation of EQ5s and 6s have green detailing--put that all together and it would make a very intimidating setup.
(With a finderscope, of course; OAGs don't look so good :p)

John

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You also have 150F4 options, they are 600mm so you will have the FOV of a 130PDS. Unfortunately SW does not sell them, by you can find almost the same (GSO) scope under the brands of GSO, Orion, Omegon and TS optics (PHOTON).

If anytime I change my 130PDS it would be with one of those, their weight in steel made tube is around 5.5kg and 3.5 in CF, so both options will fit for DSO on the available range for my AZEQ5.

Cheers.

PS: A quote for you Moise, last week I replaced the head of the AZEQ5 with one from Geoptik which allows both Vixen and Losmandy dovetails, it provides more sitting surface for the scopes.

http://www.geoptik.it/index.php?route=product/product&path=93&product_id=23

 

 

Edited by Susaron
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With an OAG I have the advantage of having both cameras hanging down, towards the RA axis. This way I need only one counterweight which doesn't sit far away from the axis.

If I were to upgrade to a 150 F/4, I would choose a carbon version, not really looking to spend all night refocusing :) Perhaps a TS UNTC OTA, the focuser appears better than ones on the PHOTON line.

On the other hand, a 150mm mirror collects only 33% more photons than a 130mm mirror. Usually I just put my 130PDS on the mount a few hours before night fall for cooling down and when it's dark, I start imaging. If I were to spend extra time fiddling with colimation, would those 33% really be recorded?

Also, a new 130PDS is 200 euros while a TS UNTC 150 F/4 with a GPU coma corrector are 1100 euros. Does it worth the extra money? I didn't even see that many images taken with these scopes.

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44 minutes ago, Susaron said:

for my AZEQ5.

By the way, how does your guiding go usually with your AZ-EQ5 and the 130? With an OAG and > 685nm IR pass filter, I usually guide for a total error of 0.8"-1.3" RMS.

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3 minutes ago, moise212 said:

By the way, how does your guiding go usually with your AZ-EQ5 and the 130? With an OAG and > 685nm IR pass filter, I usually guide for a total error of 0.8"-1.3" RMS.

To be honest I am struggling with guiding, I use a 60mm finderscope, but last Friday I suffered issues with PHD2 and my ASI385, phd2 was unable to record a proper calibration it spent a lot of time waiting for responses. All my last pictures have been taken without guiding. I also own a SW200PDS so in order to reduce weight I am seriously considering to replace the 60mm tube with an OAG in order to be used in both reflectors. I would like to ask you how difficult is to focus the guiding camera, have you any picture of your set up?, just to figure out how it looks like.

I add a picture of the AZEQ5 with the Geoptik head.

Regarding the replacement for the 130PDS you are right, a 150F4 UNC CF is around 750 eur, almost the cost of 3 130PDS, also think that CF degrades with outer exposure and specially with sunglight

P_20180427_200659.jpg

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I've one picture on my phone, I can add some more this evening if you want.

I find quite easy to focus the OAG. Done once during daytime and then adjusted under the stars. Takes a minute to adjust and you don't have to focus perfectly.

32104624_1972077789511539_1640595078059655168_n.jpg

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33 minutes ago, moise212 said:

I find quite easy to focus the OAG. Done once during daytime and then adjusted under the stars. Takes a minute to adjust

+1. There's a lot of misinformation on OAG focussing. I think this stems from years ago when they may well have been problematic. But modern cameras and focusers make them easy to manage; well worth the (not much extra and probably maybe even a bit less) extra cost for those pinpoint stars. Every time:)  Cheers.

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52 minutes ago, Susaron said:

Mmmm, then I have made up my mind, and I will go for the QHYOAG-M. Thanks gents.:hello2:

Check out also the generic one from FLO and the ZWO OAG. I believe they are thinner.

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2 hours ago, moise212 said:

upgrade to a 150 F/4

Hi. Be careful. I tried one but sent it back due to the (ridiculous) back focus. My dslr needed to be 18cm from the tube; impossible to hold rigidly and needing a long extension, even with the focuser racked out fully.

2 hours ago, moise212 said:

Perhaps a TS UNTC OTA

I think that's the sensible option as you can specify primary to secondary distances and specify a reasonably sized secondary. 

Here's a snap showing where the focal plane is located...

At6d.jpg.41933300fadba18fbf28e49787613f0c.jpg

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21 minutes ago, alacant said:

Hi. Be careful. I tried one but sent it back due to the (ridiculous) back focus. My dslr needed to be 18cm from the tube; impossible to hold rigidly and needing a long extension, even with the focuser racked out fully.

I think that's the sensible option as you can specify primary to secondary distances and specify a reasonably sized secondary. 

Here's a snap showing where the focal plane is located...

At6d.jpg.41933300fadba18fbf28e49787613f0c.jpg

option for a 150F4 discarded thanks.

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I think I'll just skip those F/4 newtons. Unless it's 200mm+ one, I don't feel they justify the cost. An F/5 SW with a SW 0.9x reducing CC is already at F/4.5. I might just buy an 150mm one and if I don't like it, I will sell it for a small loss.

I can realuminize the 130 mirror and try to image with a DSLR and an EQ5. At 1.5 arcsec/pixel with a Canon 550D I could just get away with the guided EQ5 without tossing too many subs.

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53 minutes ago, moise212 said:

Check out also the generic one from FLO and the ZWO OAG. I believe they are thinner.

No they are not, with the M54 adapter the QHY thickness is 13mm, the problem is that the QHY168C has a bigger backfocus distance than the ASI071, I have done my calculations with the TS OAG9 and it will fit well.

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3 hours ago, moise212 said:

I believe they are thinner.

Hi. I don't think it matters how thick they are as the sensor is much closer to the camera connection than the 44mm of any dslr. Any OAG should fit in the 55mm distacnce you need for your coma corrector; get one with a large prisim e.g. this one has 16mm glass. The qhy needs only 18mm so you've loads to play with.

OTOH with a dslr, you really have only one choice to get the correct distance simply.

HTH.

Edited by alacant
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