100 replies to this topic

[Mazerski]

John,

 

Filter Wheel... it works in the Boren-Simon scope (Eddgie helped me with adapters to get this to work). The wheel has a 2" Baader nosepiece on back that fits in focuser... the Mod3 slides right in - focus is achieved in the Mod3 and PVS-7 with all 5 filters (the Baader filter rings or cell is taller than the Astronomik). I don't have any issues nor does it get in the way.

 

The wheel does not work in a Mak-Cass or 15" Obsession Classic.

 

The Reflectix is a test - its been cold with lots of ice crystals... I want to see if it helps to prevent or delay fogging up of the secondary and filters in wheel. So far so good but I need more testing.

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[Vondragonnoggin]

I tried a 1.25” filter wheel in my 120ST and it did not come to focus even with the shorter GSO focuser.

[stargazer434]

Well, I already have a local, used Orion 120mm F-5 with an upgraded focuser, rings, plate, and basic diagonal to be picked up tomorrow!  Now, I will start working on the rest of the gear list.  Other than the obligatory astromart/cn classifieds/ebay, are there any other places that folks like to look for H-Alpha Narrowband Filters?  It seems to me like the Astrodon 5nm is the top choice if I were to start out with only one filter and paying retail.  Very impressed with the results I see in several threads on here.

[moshen]

I love my filter wheel but it took some effort to make it work with the back focus requirements with a 2" reducer. Basically I used a Baader T2 diagonal and used T2 connections. Shown here is mounted with a 2" GSO 0.5x reducer. I also have a 2x Barlow mounted in a 1.25" filter cell. It's really nice to switch everything up with a turn of the wheel.

 

I agree it's overkill and not necessary to figure out to start. But something to consider experimenting with in the future.

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[Mazerski]

Filters...

 

never looked thru with 5nm - I had the Baader 7nm for a year before I got the Astronomik 6.

if I had your choice, I would skip the 5nm and get the 6 or 7 (depending on where you live and status of LP) AND get a Astronomik 642nm IR. You need both to appreciate NV. 

 

I cant decide if I prefer M42 with Ha filter or the 642 IR... the 642 still shows a lot of emission gas plus many more stars.

[stargazer434]

That is actually a good point.  I can be out the door for $250 with an Astronomik 6nm HA and a 642nm IR.  I think that would be a good place to start.

Edited by stargazer434, 22 February 2019 - 03:13 PM.

[Vondragonnoggin]

That is actually a good point.  I can be out the door for $250 with an Astronomik 6nm HA and a 642nm IR.  I think that would be a good place to start.

I think those would be excellent choices and reasonably priced. I think you are on your way to a complete list to start

[stargazer434]

Nice, I have the Astronomik 6nm HA and 642nm IR 1.25" filters, Scopestuff C-Mount to 2" Eyepiece, Antares 2" 0.5x Focal Reducer, used Orion 120mm F-5 with rings/plate/diag, and MOD-3.  Now, I just need a mount and should be up and running this coming week to try everything out.  Thanks again everyone!

Edited by stargazer434, 22 February 2019 - 03:53 PM.

[Jeff Morgan]

Sounds like I should elbow the filterwheel idea as expensive overkill and to avoid back travel focuser problems because I will want a good 0.5 reducer on whichever scope I choose in the end.

I would not say it is expensive - but they do have some associated issues. Really, just a matter of prioritization.

 

Another avenue you may want to explore are filter drawers. Almost the same convenience as a wheel with less bulk and potentially less back focus issues:

 

https://www.teleskop...ngth-15-mm.html

https://www.baader-p...-filter-chamber

 

GeezerGazer uses something like these with his 300mm telephoto lens. Might actually make more sense than the usual telephoto adapters, I need to look closer at that myself. That whole Prioritization thing 

 

Just my $.02

While you’re getting the 2” .5x reducer you might as well get the .7x as well. I use both, though I use the .7x more. IMO, 3nm is pretty narrow. Depending upon the night, I actually tend to use my 12nm more often than my 6nm, but I’ve never wished for any narrower than the 6nm. FWIW, both of mine are Astronomik filters.

Yes, the 2" 0.7x reducer is nice to have. Hard to wrong for only $50. Especially if you use the device with Newtonians, which are challenged for back focus distance. 

 

I took some approximate measurements on my 16" Newtonian and an AstroTech 60ED refractor and they were consistent. 12-15mm back focus to use a 0.7x reducer, 55-58mm to use a 0.5x reducer (on the refractor, the Newtonian could not do it).

 

With regards to filter choices, lots of great advice here. In the end your optimum choice will be a mix of aperture, speed, target, and personal preference. When you use a filter that is "lighter" (specifically, the 12nm) it is not easy to know if you have "optimum" filtration. On the other hand, when you use too "heavy" a filter, you will know it right away!

[Doug Culbertson]

I would not say it is expensive - but they do have some associated issues. Really, just a matter of prioritization.

 

Another avenue you may want to explore are filter drawers. Almost the same convenience as a wheel with less bulk and potentially less back focus issues:

 

https://www.teleskop...ngth-15-mm.html

https://www.baader-p...-filter-chamber

 

GeezerGazer uses something like these with his 300mm telephoto lens. Might actually make more sense than the usual telephoto adapters, I need to look closer at that myself. That whole Prioritization thing 

 

Yes, the 2" 0.7x reducer is nice to have. Hard to wrong for only $50. Especially if you use the device with Newtonians, which are challenged for back focus distance. 

 

I took some approximate measurements on my 16" Newtonian and an AstroTech 60ED refractor and they were consistent. 12-15mm back focus to use a 0.7x reducer, 55-58mm to use a 0.5x reducer (on the refractor, the Newtonian could not do it).

 

With regards to filter choices, lots of great advice here. In the end your optimum choice will be a mix of aperture, speed, target, and personal preference. When you use a filter that is "lighter" (specifically, the 12nm) it is not easy to know if you have "optimum" filtration. On the other hand, when you use too "heavy" a filter, you will know it right away!

 

Thanks for mentioning the back focus with the .7x reducer, I forgot about that. On my 10” SkyWatcher flex tube dob, I can use both reducers with no modifications or having to lower the trusses. This comes at the expense of having to use an extension tube for eyepieces, but I bought this telescope strictly for NV use anyway. On my former AT72EDII I couldn’t reach focus with any reducers, 2” or 1.25”, hence it being my former scope. 

[stargazer434]

On the Orion 120ST I just picked up, it has the upgraded Orion dual speed focuser:

 

https://www.telescop...ser/p/13032.uts

 

Will it have any back travel issues with the reducer and 2" diag?

[Vondragonnoggin]

On the Orion 120ST I just picked up, it has the upgraded Orion dual speed focuser:

 

https://www.telescop...ser/p/13032.uts

 

Will it have any back travel issues with the reducer and 2" diag?

 

Maybe someone that has that version of dual,speed will chime in, but to me it is too difficult to tell just from the picture of the focuser by itself. You might try to take a photo of the tail end of your telescope and match it in scale to the pictures of the Orion 120ST in the thread I linked earlier, and see if it seems substantially longer or roughly same length or get some type of reference to the original single speed which did not allow enough back focus for a .5x reducer. Probably would be enough for a .7x though.

[stargazer434]

Hmm, I might as well order a GTO focuser anyway.  Which one on Scope Stuff works with the Orion 120ST? 

[Vondragonnoggin]

Hmm, I might as well order a GTO focuser anyway.  Which one on Scope Stuff works with the Orion 120ST? 

I would wait and try out your setup first. They won’t run out of Crayford focusers. I believe the info is in the thread I linked for what cw00 used on his Orion, but do try out yours first. He had the original single speed on his and that was why he upgraded. He just happened to find out after getting the focuser and adapter plate that it significantly increased backfocus for him allowing reducers to work well.

[outofsight]

On the Orion 120ST I just picked up, it has the upgraded Orion dual speed focuser:

 

https://www.telescop...ser/p/13032.uts

 

Will it have any back travel issues with the reducer and 2" diag?

I have a focuser like that on my 120ST. As far as I can remember I had some initial trouble achieving focus with a 2" diagonal and a PVS-7 (Your monocular may work right out of the gate). I don't remember all the machinations I went through, it might have been just switching to a different 2" diagonal, and also making sure that the diagonal holder was screwed as far into the focuser tube as possible.

 

You should mess around with it first, keeping the GSO focuser in mind in case things don't easily work out. And here's what I did, at one point, that immediately solved the focus problem, I put a 1.25" diagonal in, and it was easy to get focus so then I could take my time and figure everything else out from there.

Edited by outofsight, 25 February 2019 - 05:30 PM.

[stargazer434]

Ugh, it turns out even the upgraded orion 2 speed focuser is a complete dog.  Barely useable.  Definitely want to upgrade to a GSO.  Anyone know the exact model to order?  Everything else is coming together though.  Picked up a preowned Stellarvue M2C alt alz mount and Manfrotto tripod.  Just need a few more odds and ends and some clear skies to fire it up.

[Vondragonnoggin]

Ugh, it turns out even the upgraded orion 2 speed focuser is a complete dog.  Barely useable.  Definitely want to upgrade to a GSO.  Anyone know the exact model to order?  Everything else is coming together though.  Picked up a preowned Stellarvue M2C alt alz mount and Manfrotto tripod.  Just need a few more odds and ends and some clear skies to fire it up.

Bottom of the page is contact info. Give them a call and they can set you up with correct focuser and adapter plate for your scope.

 

http://www.scopestuff.com/index.html

 

They are very familiar with the Orion and other branded 120ST’s

Edited by Vondragonnoggin, 27 February 2019 - 10:03 PM.

[Vondragonnoggin]

Here is the link for what cw00 pulled from the ScopeStuff page. He is also using a GSO linear bearing focuser and adapter is for 112.5mm

 

https://www.cloudyni...back/?p=6917761

 

I specifically chose my linear bearing because it has a 9lb rating and I’m using a heavy pvs 4 converted starlight scope with gen 3 tube and a 4” biocular eyepiece. It’s pretty weighty. The drawtube is only 50mm on the linear bearing focusers,but cw00 did measure 3.5” from tube to end of focuser compared to original 5.7”

Edited by Vondragonnoggin, 27 February 2019 - 10:52 PM.

[stargazer434]

Initial setup is ready to go!  Now the wait for clear skies begins...

 

 

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Edited by stargazer434, 05 March 2019 - 08:00 PM.

[Vondragonnoggin]

Looks great.  Is that an M2C or M2? I have the M2 I use with my 120ST and it works great. I put the steering arm on it too. Steering arm is kinda short but works to keep my hands off the tube or diagonal. That is still the Orion dual speed, right? Let us know how it goes with it when you get a clear night. You’ll be amazed by the views with the 120. 

 

Which Manfrotto is that?

[stargazer434]

Looks great.  Is that an M2C or M2? I have the M2 I use with my 120ST and it works great. I put the steering arm on it too. Steering arm is kinda short but works to keep my hands off the tube or diagonal. That is still the Orion dual speed, right? Let us know how it goes with it when you get a clear night. You’ll be amazed by the views with the 120. 

 

Which Manfrotto is that?

Thanks!  I'm looking forward to it and will keep you posted.  The mount is the M2C and tripod is the Manfrotto 475B.  I really wanted a geared tripod like this to keep it as compact as possible for storage and to skip needing a pillar.  I bought them both together used from a nice CN member based up in Seattle.  Yep, still the two speed for now.  It will be replaced shortly, lol.  I'm also going to try to find a good hardcase and tripod bag combo for them eventually as well. 

[Vondragonnoggin]

Excellent combo for that. Good luck with weather! Mine has been nonstop clouds and rain and I’m itching to get the scope out again.

[jcj380]

Initial setup is ready to go!  Now the wait for clear skies begins.

So you just plug that puppy into your diagonal and away you go?  Wow.  I'm going to have to seriously consider this.

[stargazer434]

So you just plug that puppy into your diagonal and away you go?  Wow.  I'm going to have to seriously consider this.

Pretty much!  I just have the MOD 3 NV monocular attached to a 2" scope stuff c-mount adapter with a 1.25" 6nm ha filter screwed into it and a 0.7 2" focal reducer screwed on too.  Otherwise, it is all business as usual.  Folks on here were invaluable in pointing me in the right direction.

Edited by stargazer434, 08 March 2019 - 12:38 PM.

[stargazer434]

Well, tonight was the first clear night out, and it was a bust, unfortunately. Somehow it seems like I don’t have enough in-focus travel. I would have thought that back-focus would have been the problem. I guess I’ll need to upgrade the focuser first, wah wah.