Imaging with the 130pds

[cuivenion]

It depends on your climate, if you're lucky you may just be able to use a dew shield. I would go with a secondary mirror heater over a heated dew shield though. I recently tried a heated dew shield and that didn't work well. I tried insulating the back of the secondary mirror with polyethylene foam and tape and also used a dew shield. That seems to be working for me at the moment.

[Adam J]

16 minutes ago, jjosefsen said:

Hi.

 

I'm considering getting one of these bad boys (130pds) and modifying it over Christmas.

I'm looking at dewheater solutions, and wondering if a glued secondary mirror heater would be preferable to a dewshield.

Can any of you tell me the diameter of the secondary mirror stalk/mounting?

I was considering mounting an rca plug in the top of the ota for a more permanent solution instead of having a cable dangle lose up there.

I dont use a heater, I do use a dew shield. It has to be very high humidity 85% before I have problems and that is usually associated with poor transparency anyway.

I have only had it dew up once this year and I suspect that was because I needed to remove the dew shield to refocus with the mask.

I think that some of this is to do with using a obsy though and I do remember it being worse before I got the obsy.

I would see how you get on with a dew shield before you go to the trouble of adding a heater to the secondary. The most important mod is that you, cut the focuser tube (unless you get the ES corrector).

Adam

[jjosefsen]

45 minutes ago, Adam J said:

I dont use a heater, I do use a dew shield. It has to be very high humidity 85% before I have problems and that is usually associated with poor transparency anyway.

I have only had it dew up once this year and I suspect that was because I needed to remove the dew shield to refocus with the mask.

I think that some of this is to do with using a obsy though and I do remember it being worse before I got the obsy.

I would see how you get on with a dew shield before you go to the trouble of adding a heater to the secondary. The most important mod is that you, cut the focuser tube (unless you get the ES corrector).

Adam

I often have very high relative humidity 90+.. with my frac and a dew band it's not an issue, but it worries me with the open design of a newt.

I must admit I was hoping I didn't have to cut the draw tube with the cc I'm looking at.

Can anyone tell me the diameter of the stalk the secondary mirror is mounted on?

[alacant]

10 hours ago, jjosefsen said:

diameter of the secondary mirror stalk

Hi. 35mm. HTH.

[Uranium235]

12 hours ago, jjosefsen said:

Hi.

 

I'm considering getting one of these bad boys (130pds) and modifying it over Christmas.

I'm looking at dewheater solutions, and wondering if a glued secondary mirror heater would be preferable to a dewshield.

Can any of you tell me the diameter of the secondary mirror stalk/mounting?

I was considering mounting an rca plug in the top of the ota for a more permanent solution instead of having a cable dangle lose up there.

Just go with thte dew shield, no need for a secondary heater

I made a my dewshield out of a small bucket (actually it was a from a small bucket of sweets, about 12 inches in height), where I'd cut the bottom off (which matched the aperture exactly) and then flocked the inside. It works perfectly and Ive never had an issue with fogging, not unless a load of mist rolls in and it starts "falling" (like rain) onto the primary mirror.... in which case you shouldnt really be out...lol.

Just have a look around the house or shed, and try to spot things that might fit the aperture - there is always something you can use/modify to fit.

[RolandKol]

Here is my second try on the Flaming Star Nebula.

SHO, - only 12x300s each, Baader NB (7<>8.5nm) + ASI1600MM-Pro.
Planing to add a bit more Ha and SII, not sure about OIII as images showed almost no dust...

Should I try adding OIII anyway?

 

[Stub Mandrel]

I use a dewshield made out of a camp mat, about 30cm long.

[Susaron]

17 hours ago, jjosefsen said:

Hi.

 

I'm considering getting one of these bad boys (130pds) and modifying it over Christmas.

I'm looking at dewheater solutions, and wondering if a glued secondary mirror heater would be preferable to a dewshield.

Can any of you tell me the diameter of the secondary mirror stalk/mounting?

I was considering mounting an rca plug in the top of the ota for a more permanent solution instead of having a cable dangle lose up there.

The secondary has a 48mm secondary axis. Anyway I have shared a season with refractor colleagues with a 100% humidity beside a river and whereas they had their dew strips at 100% power, mine one was absolutely dry with camping mat outside the tube and some flocking inside.

Edited December 10, 2018 by Susaron

[jjosefsen]

5 minutes ago, Susaron said:

The secondary has a 48mm secondary axis. Anyway I have shared a season with refractor colleagues with a 100% humidity beside a river and whereas they had their dew strips at 100% power, mine one was absolutely dry with camping mat outside the tube and some flocking inside.

Ok that sounds encouraging. Maybe I will just go with a dew shield and not a heater.

I plan on flocking it straight away, so wanted to do the dew heater in the same gon if necessary.

Thanks for the feedback.

[sagramore]

On 09/12/2018 at 21:08, jjosefsen said:

I often have very high relative humidity 90+.. with my frac and a dew band it's not an issue, but it worries me with the open design of a newt.

I must admit I was hoping I didn't have to cut the draw tube with the cc I'm looking at.

Can anyone tell me the diameter of the stalk the secondary mirror is mounted on?

I would add that you can avoid cutting the draw tube if you are willing to modify the scope to move the primary mirror up the tube a little. There are a couple of us in this thread that did it - it's a reversible modification and works perfectly to bring the focal plane out so the draw tube doesn't protrude into the aperture too much. Sorry I can't find the exact posts but if you are able to search (or scroll through!?!) this thread then at least 2 of us have photos and descriptions of how we did it.

Just a thought!

[jjosefsen]

Do any of you know if this adapter (10mm) has a shorter optical length than the standard 2" adapter on the scope?

https://www.firstlightoptics.com/adapters/flo-compression-ring-adapter-for-skywatcher-newtonians-m54.html

 

I have one of these for my frac, and can't say I find it much better than the usual thumbscrew version. But if it is shorter it could help with the draw tube problem..

 

[Stub Mandrel]

It's definitely not shorter than the standard adaptor, I think the standard one is 10mm too, but I've made a pair of slightly shorter ones. It's not really practical to fit a compression ring to one much smaller than 10mm.

[jjosefsen]

30 minutes ago, Stub Mandrel said:

It's definitely not shorter than the standard adaptor, I think the standard one is 10mm too, but I've made a pair of slightly shorter ones. It's not really practical to fit a compression ring to one much smaller than 10mm.

Yeah I thought as much.. Well I plan on ordering scope, collimation tools, thumbscrews for secondary and flocking material tonight. So hopefully this can be my little Xmas project. Then dewshield and CC after next payday. ?

[Adam J]

5 minutes ago, jjosefsen said:

Yeah I thought as much.. Well I plan on ordering scope, collimation tools, thumbscrews for secondary and flocking material tonight. So hopefully this can be my little Xmas project. Then dewshield and CC after next payday. ?

Did you decide which CC your going for in the end?

 

[jjosefsen]

6 minutes ago, Adam J said:

Did you decide which CC your going for in the end?

 

Yeah 95% sure it is going to be the 3-element maxfield CC from TS Optics.

https://www.teleskop-express.de/shop/product_info.php/info/p3822_TS-Optics-2--3-element-MaxField-Newtonian-Coma-Corrector.html

 

[jjosefsen]

21 minutes ago, Adam J said:

Did you decide which CC your going for in the end?

 

I am still haunted by by the ES HR CC as well.. It is a little shorter than some at around 85mm compared to the 100mm of the GPU.

If I didn't worry about the length of the GPU then that woul probably be my choice..

Basically it is one of these:

ES HR - More expensive, but better, especially if I am going to get a faster scope in the future, slightly longer.

TS Maxfield: Cheaper, shorter meaning less problems with the 130pds focuser, should still be a decent improvement over the Baader MPCC.

[Adam J]

6 minutes ago, jjosefsen said:

I am still haunted by by the ES HR CC as well.. It is a little shorter than some at around 85mm compared to the 100mm of the GPU.

If I didn't worry about the length of the GPU then that woul probably be my choice..

Basically it is one of these:

ES HR - More expensive, but better, especially if I am going to get a faster scope in the future, slightly longer.

TS Maxfield: Cheaper, shorter meaning less problems with the 130pds focuser, should still be a decent improvement over the Baader MPCC.

I still think that with your size of sensor you will have no issues with the Baader MPCC MkIII you wont see much difference with the more expensive corrector on the 130PDS its more about if you want to get that F4 scope in the future along with a larger sensor. But I do understand you wanting to future proof your purchase.

[serbiadarksky]

I just saw this topic.

My first plan was to go for a 150PDS and EQ5 for imaging (with guiding etc)

Than I saw the 130PDS and wow I am in love with it!

Will it be totally ok to do imaging with the 130PDS instead of 150PDS on EQ5 Pro goto? The 150PDS is just under the limit, so I guess the 130PDS will work perfectly with that mount.

[JohnSadlerAstro]

Hi,

My first data this year! I cant believe its been so long, but finally I'm back to imaging again! ? The NEQ6 worked a dream, an average of around 1" total RMS over the night, for 4 hours! I was able to keep around 80% of the frames, too. 

NGC2403, A difficult target that's probably a NASA copy-paste of M33. ????  

130PDS on NEQ6, Guided with ASI120MC and 50mm finder

1000d, 200sec subs at ISO 800, 3hr 30mins

DSS, PHD2, GIMP Star Tools

It's a really exciting area of the sky, loads of galaxies and some beautiful colour contrasting binaries. The processing is pretty awful, but there was a really large gradient on each side of the image that was a big pain to remove and took most of the colour with it.  

I put picture alongside some 100x100 crops to highlight all the little fuzzies.

And then compiled them into a table, because the weather was bad. (Square brackets are my data, SIMBAD and the NED are disappointingly incomplete)

It's a testament to the miraculous abilities of the 130PDS that I could catch a magnitude 19.4 active galaxy with very newbish processing, a bad camera and a complete lack of experience over the 12 months. 

Clear skies!

John

Edited December 17, 2018 by JohnSadlerAstro

[Stub Mandrel]

Back with a bang, John!

[JohnSadlerAstro]

33 minutes ago, serbiadarksky said:

I just saw this topic.

My first plan was to go for a 150PDS and EQ5 for imaging (with guiding etc)

Than I saw the 130PDS and wow I am in love with it!

Will it be totally ok to do imaging with the 130PDS instead of 150PDS on EQ5 Pro goto? The 150PDS is just under the limit, so I guess the 130PDS will work perfectly with that mount.

Hi,

Yes, for size and weight those two are very nicely matched. However, I would just warn you about using the EQ5 for guiding--I tried it and it was quite frustrating, I ended up upgrading to a used NEQ6. It might be worth considering an HEQ5, which is really designed for astrophotography--it is also a bit sturdier so it will be able to hold the 130 really steady.  

Hope this helps,

John

[serbiadarksky]

30 minutes ago, JohnSadlerAstro said:

Hi,

Yes, for size and weight those two are very nicely matched. However, I would just warn you about using the EQ5 for guiding--I tried it and it was quite frustrating, I ended up upgrading to a used NEQ6. It might be worth considering an HEQ5, which is really designed for astrophotography--it is also a bit sturdier so it will be able to hold the 130 really steady.  

Hope this helps,

John

I have never heard about guiding issues with eq5, all what I heard was that it cant take a big scope..btw I wanted a 150PDS, now I am concerned about 130PDS and can the mount do ap with it..and at the end I found a guy doing 15min exposures with EQ5 and 200/1000(9.5kg scope) lol..

[cuivenion]

5 hours ago, serbiadarksky said:

I have never heard about guiding issues with eq5, all what I heard was that it cant take a big scope..btw I wanted a 150PDS, now I am concerned about 130PDS and can the mount do ap with it..and at the end I found a guy doing 15min exposures with EQ5 and 200/1000(9.5kg scope) lol..

It all depends on your budget and what equipment you already have. People have got good results with the EQ5 and similar mounts, but the lower the quality of the mount the harder it is. For visual the EQ5 and 130PDS are well matched but for AP a HEQ5 will be a real step up, I've used both mounts and I'd definitely go for the HEQ5 if you can.

[Stub Mandrel]

I got away with a 130P-DS on an EQ3 for a year or two.

 

[serbiadarksky]

7 hours ago, cuivenion said:

It all depends on your budget and what equipment you already have. People have got good results with the EQ5 and similar mounts, but the lower the quality of the mount the harder it is. For visual the EQ5 and 130PDS are well matched but for AP a HEQ5 will be a real step up, I've used both mounts and I'd definitely go for the HEQ5 if you can.

Well, I respect your words, but I have been told several times that EQ5 and 130PDS can work perfectly for imaging.