So, how about that Skywatcher Explorer 250P DS?

[Alveprinsen]

Looks like I need a new scope.

My 600mm Evostar 80ED Pro just doesnt cut it for me anymore when it comes to F-ratio. I need something that can really collect buckets of photons and get me closer up details.

So, I am considering the Skywatcher Explorer 250P DS. some questions though:

1. I have no experience with Newtonians. What extra equipment will I need for this scope in order to get it focused and such with my Nikon DSLR?Spacers? Field flattener? Coma corrector or whatnot?

2. What about this colimation business? Is this something one has to do all the time? I guess I need one of those laser-thingies?

3. Is it ok to guide this huge cannon of a scope with a side-by-side 600mm refractor?

4. How about dew? Do they easilly get dew on secondary and/or primary mirror? how do I counter this? Heater tapes? Shields? ...

Oh, and last but not the least... with an EQ6 Pro mount, how much counterweight would I need, my tracking scope not included...? I got like 15kg of counterweights right now, but.. dont wanna end up short...

sincerely, Alveprinsen.

[ollypenrice]

Coma corrector, off axis guider, essential. The mount will be marginal on anything but still, windless nights.

You'd need to collimate nightly but with the right tools you might get to be very good at it.

Personally I like refractors. A Tak FSQ85 can work at F3.9 in perfect ease... 

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/i-rNfQT5R/0/X3/M42%20WIDE%202FLsV3-X3.jpg

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/i-SVkkwzW/0/X3/ROSETTE%20FIN3WEB-X3.jpg

The focal length is short, though. Unlike the price!

Olly

[Alveprinsen]

Coma corrector, off axis guider, essential. The mount will be marginal on anything but still, windless nights.

You'd need to collimate nightly but with the right tools you might get to be very good at it.

So I guess side-by-side guiding with a 600mm refractor is a no-go with a 1200mm reflector?

I do have an OAG, but its a relatively cheap one. The "tube" of the OAG is a bit long too... Its not as short and compact as others. Will this give me trouble with focusing the scope?

Nightly collimation huh? ... yuck... I better get one of those Uber laser thingies then...

I prefer refractors myself, however - focal length and price is of the issue here.

[nicks90]

Nightly collimation huh? ... yuck... I better get one of those Uber laser thingies then...

as long as you dont plan on chucking the ota down the stairs on a regular basis - then collimation should be a tiny tweak to the primary - if at all. And yes a collimated laser collimator makes it a 5 second job and well worth the pennies.

[RikM]

I can confirm that the NEQ6 + 250PX catches the wind if you're out in the open. I use a finderguider rather than OAG (nuts I know) but with that light setup, 2x 5kg weights on the extension bar are enough. I have a simple foam dew shield on the front and that has been sufficient dew control for all but the very worst nights.

[Alveprinsen]

I can confirm that the NEQ6 + 250PX catches the wind if you're out in the open. I use a finderguider rather than OAG (nuts I know) but with that light setup, 2x 5kg weights on the extension bar are enough. I have a simple foam dew shield on the front and that has been sufficient dew control for all but the very worst nights.

Thank you for that bit of info...

Do you tihnk I could do side-by-side guiding with a 600mm refractor though? Since you using a finderguider? What is your experience?

[RikM]

I think an ED80 as a guide scope on a 250PDS NEQ6 should be doable but may be difficult; they are quite heavy for the size. I have not shot many images with the 250PX and only one worth posting because I have to set up in the garden each night and I don't have an effective windbreak yet. The finderguider seems to be working for me, but the general consensus is that an OAG would give better more consistent results. I guess I will cross that bridge when I get fed up with the finderguider. I also have an ST80 to use as a 400mm guider option but haven't used it with the 250PX yet.

My plan was to use the 250PX for a bit more focal length on planetary nebulae but I prefer the slightly wider field I get with the 150P, so generally 'look' through the 250PX in Dob mode.

Here is a 5min guiding test-shot with a DSLR (not proper processing because only a test, 3x 5min I think

And a CCD shot with the H9 and filters (loads of jpeg artefacts, sorry) I can't remember the sub lengths. I think up to 15min in Ha? I have done a couple of 30min shots just to see if I could. One was okay, one got killed by the breeze.

I'm building an obsy in the spring, so will do more imaging with the 250PX when I can leave it set up for a month at a time.

[Alveprinsen]

I think an ED80 as a guide scope on a 250PDS NEQ6 should be doable but may be difficult; they are quite heavy for the size...

... but the general consensus is that an OAG would give better more consistent results....

...Here is a 5min guiding test-shot with a DSLR (not proper processing because only a test, 3x 5min I think....

Well, the big newtonian is like 14,5kg? and the 600mm refractor is 2,5kg. A total of 17kg, which is well within what the NEQ6 Pro can handle.

I dont know what recommended weight for the NEQ6 Pro is for imaging. For viewing I guess you could just about max out the load capacity, but for imaging?

Anyone got any experience with that? FLO product description says 18kg for imaging.

[Alveprinsen]

Here is a 5min guiding test-shot with a DSLR (not proper processing because only a test, 3x 5min I think

Looks pretty nice if you ask me. Seems your guiding is working just fine.

[RikM]

Well, the big newtonian is like 14,5kg? and the 600mm refractor is 2,5kg. A total of 17kg, which is well within what the NEQ6 Pro can handle.

I dont know what recommended weight for the NEQ6 Pro is for imaging. For viewing I guess you could just about max out the load capacity, but for imaging?

Anyone got any experience with that? FLO product description says 18kg for imaging.

Plus the mounting hardware, coma corrector, imaging camera, guide camera, dew bands, cables etc.

To be honest it is more the physical size / length of the OTA that taxes the mount rather than the weight. Going by the recommended payload may well give a false impression of how it will work. I am sure it would do it, I just couldn't estimate what the yield would be (how many sub you loose to windshear). It is quite possibly no different from just the 250PDS on its own.

Do you particularly want the longer focal length / smaller field of view? Or are you just looking for a faster optical speed over your ED80? A 130PDS plus 0.9x coma corrector (operating at f/4.5) should comfortably beat your ED80 on optical speed, with a very similar field of view and better colour correction.

[Naemeth]

How about an MN190 instead? Still fast, but offers a nice corrected field, and is well within the limits of the NEQ-6 mount.

[Alveprinsen]

...Do you particularly want the longer focal length / smaller field of view? Or are you just looking for a faster optical speed over your ED80? A 130PDS plus 0.9x coma corrector (operating at f/4.5) should comfortably beat your ED80 on optical speed, with a very similar field of view and better colour correction.

Focal length. I want to get close up and personal with some of the smaller objects out there. 1200mm isnt a whole lot for many of the small objects out there, but its twice of my 600mm, and faster too. With the 1200mm, I could possibly even slip in a barlow, and still be below F-10. sure, I'd need long exposures etc. But at least it would be doable. With my 600mm this would be an absolute no-go.

the 130P DS has about the same focal length as my 600mm Evostar ED - so thats a negative. 1200mm is what I am looking for, and preferably fast as well.

I HAVE been looking at a Bresser Messier 152/1200 at F 7,9 - but that would land me at the same F-ratio I got now. Which is fine, sort of... Although faster scope would be cool. Its freakishly long and heavy though, which is to be expected.. but still.

I also dont know how well these Bresser scopes are. I mean, its not exactly expensive at 476 Euro. I just worry that I'll have problems with chromatic aberration - like I did with my Startraveler 102/500... Absolutely horrible chromatic aberration...

Alveprinsen.

[Alveprinsen]

How about an MN190 instead? Still fast, but offers a nice corrected field, and is well within the limits of the NEQ-6 mount.

Way too expensive. thats the kinda cash I am looking to spend on a JTW Ultimate Deep Cooled Canon 1100D V3 which I'm trying to get feedback on in a separate thread.

[RikM]

Focal length. I want to get close up and personal with some of the smaller objects out there. 1200mm isnt a whole lot for many of the small objects out there, but its twice of my 600mm, and faster too. With the 1200mm, I could possibly even slip in a barlow, and still be below F-10. sure, I'd need long exposures etc. But at least it would be doable. With my 600mm this would be an absolute no-go.

the 130P DS has about the same focal length as my 600mm Evostar ED - so thats a negative. 1200mm is what I am looking for, and preferably fast as well.

I HAVE been looking at a Bresser Messier 152/1200 at F 7,9 - but that would land me at the same F-ratio I got now. Which is fine, sort of... Although faster scope would be cool. Its freakishly long and heavy though, which is to be expected.. but still.

I also dont know how well these Bresser scopes are. I mean, its not exactly expensive at 476 Euro. I just worry that I'll have problems with chromatic aberration - like I did with my Startraveler 102/500... Absolutely horrible chromatic aberration...

Alveprinsen.

Good. Just so are thinking about getting one for the right reasons Exactly the same reasons, I bought mine and I haven't been disappointed.

[Naemeth]

Way too expensive. thats the kinda cash I am looking to spend on a JTW Ultimate Deep Cooled Canon 1100D V3 which I'm trying to get feedback on in a separate thread.

It is rather.

As RikM has said, at least you're getting one for the right reasons. Make sure you've got the 250PDS well balanced and try and maybe a wind-break would be a good addition?

[Alveprinsen]

It is rather.

As RikM has said, at least you're getting one for the right reasons. Make sure you've got the 250PDS well balanced and try and maybe a wind-break would be a good addition?

Theres almost no wind here... If theres wind, theres clouds - in which case I'm not out anyways.

[Paul M]

I can't help with imaging but I just got the 250PDS and NEQ6pro from Opticstar.

Their website noted that I'd need the optional extra counterweight to balance that OTA alone.

On first setting up I tried it with just the 2 weights supplied as standard but needed the 3rd one. That's without the extension bar though. I guess that just the 2 weights will do if hung out further on the extension.

I didn't try it. I preferred the more compact setup so far.

Here's my "First Light" thread: http://stargazerslounge.com/topic/195924-first-light-skywatcher-explorer-250pds-and-neq6-pro/

There might just be something of interest in there

[Alveprinsen]

I can't help with imaging but I just got the 250PDS and NEQ6pro from Opticstar.

Their website noted that I'd need the optional extra counterweight to balance that OTA alone.

On first setting up I tried it with just the 2 weights supplied as standard but needed the 3rd one. That's without the extension bar though. I guess that just the 2 weights will do if hung out further on the extension.

That is actually quite interesting information. I allready have 3 x 5kg counterweights, but I might just order an extra one if I am going to have two scopes mounted for side-by-side guiding. Unless I give the off-axis guider a shot...

[RikM]

You only need two if you use the extension bar. This is with the DSLR and a finder guider, but it was pretty much the same with the CCD and filterwheel. You would likely need three for a separate guidescope.