Barlows or Eyepieces - where is money best spent?

[ZoomerPhil]

Hi all.

New to the forum and just starting out in this area, primarily for imaging as I come with a strong photographic background.

Been planning for a while, now taking the plunge, and so want to go for quality kit from the start.

I have decided for my purposes to plumb for a 5" apx refractor with a decent mount - SKywatcher Espirt 120 and EQ6 probably - but am a little confused over where best to spend what little budget is left on eyepieces and barlows.

The scope is mainly to be used by me for astrophotography but my kids also want to get involved so need to have some options for visual use.

After speaking to a couple of friends who are keen skywatchers and some dealers, I am still unsure how best to approach the barlow/eyepiece aspects.

My initial plans were to use my DSLR (D800) direct to the scope and use barlows to add magnification - maybe a televue Powermate 2x for starters, or possibly bigger.

Not sure if its also possible to use Nikon teleconvertors instead (or in addition) of Barlows, as I have the 1.4x and 1.7x TCs.

Scope comes with a standard 28mm eyepiece so would have both photo options and some viewing options with the one eyepiece and adding a barlow if needed.

However dealers have been recommending I actually shoot through eyepieces and try to avoid Barlows, and are proposing Pentax XW EPs - a 20mm and a 7mm.

Im not sure if I can attach the camera direct to those EPs, so its also been suggested I go for cheaper Baader Hyperion EPs which have a suitable thread, and if I want a Barlow as well to go for a Skywatcher ED one.

But i dont want to waste the money spent on the scope/mount by degrading my imaging using cheaper EPs. barlows or imaging methods.

I really want to play the field with imaging - as soon as I can I want to try deep sky as my ultimate goal, but will start with the kids on the moon, and maybe hunt a planet or two.

Any suggestions on the best way to go on the basis of a 120mm refractor and EQ6?

Going for a quality refractor and mount is pushing the budget already, and spending hundreds more on both eyepieces and barlows wasnt in the plan!

While writing, I had also considered the Meade 5/6000s but the only option still available seems to be the 6000/130mm, and its pushing the cost a bit too far!!

Does anyone have any experience to justify an extra £500+ for a Meade 130mm over the Esprit 120?

As I see it , while both are pretty good quality triplets, the Meade needs a lot more spent on accessories as well as the higher initiaL scope cost.

Cheers for any advice!

ZoomerPhil

[Stargazer_00]

Hi ZoomerPhil

some pretty advanced questions there. You may be better off putting a post in the imaging section where the experts live. Not guarentees your going to get someone with that sort of expertise trawling the begginer area as the leve of advice required up here is usually less advanced. Wait and see how the thread pans out and if you dont get what you're after try again in the imaging discussion area.

All the best

[ronin]

First you do not add a barlow for astrophotography, you can if it is planetary imaging but for the DSO stuff then no barlow, just attach the DSLR to the scope. Reason is that DSO's are faint, a barlow makes them fainter.

As to Pantax's etc, well BST Explorers will do as well in the vast majority of instances, they are £47 so a fair bit less.

The Meade triplet - there is a report somewhere, here or CN, that reports some concerns. The images (stars) are seemingly purple fringed. Just the one report made but on that basis I guess you may be happier sticking with the Espirit. An image taken was attached and there is a purple hint present.

The original question (I am one biased to single eyepieces) if you get a barlow it needs to be good. The result of a poor eyepiece and a poor barlow is something the swear filter here will block.

For eyepieces only:

The 120 is f/7, on that basis how about the Celestron X-Cels eyepieces ?

They do a 5mm, 7mm, 9mm which should cover all the higher magnifications and a 25mm.

They are £69 from FLO, start with the 7mm (equal to the scope f number) for 120x.

The scope should take the 5mm with no problems, the 2.3mm may be a little OTT.

If you wanted to start with 2 then the 7mm and the 18mm or 25mm, I suspect the 18mm would be nice, but the 25mm has wider views.

The BST's and the X-Cells are very close to the extent that some people like one others like the other eyepiece, so it seems close to a match in performance. The choice is therefore 3 BST's (£141) or 2 X-Cels (£138). I have the BST's but have never used an X-Cel to voice an opinion on any difference in performance.

Barlow:

If you go for a barlow then you are looking at something like a TV powermate, simply not to degrade the scope performance. They are not cheap but you would have it forever knowing that it, in itself, would not pull the performance down.

One immediate problem of a barlow is you would still need a decent eyepiece to use with it. So if you got a 2x barlow then a 12mm BST or X-Cel which give a 12mm and a 6mm.

[bomberbaz]

I have a bst and two celestron x cel eps. For what its worth i prefr the x cels but thats just me.

[E621Keith]

Rather than a barlow to increase magnification, you will need a reducer to decrease magnification and a flattener to flatten the focal plane.

Then there is the camera. A D800 with a 36MP FX sensor is going to be very demanding on a telescope. I think the Espirit flattener only supports APS-C sized chip or smaller (as do most telescope flattener), but I could be wrong.

If you want to image with a 35mm sensor, you will need a Takahashi FSQ or one of a Borg 125SD or 77EDII, with 7887 0.85x DGL reducer or 7704 F4 super reducer or a 71FL with 7870 0.7x triplet super reducer.

http://www.firstligh...telescopes.html

http://www.iankingim...hp?category=182

Since your main interest is AP, I'd just get a Baader 8-24mm Hyperion Click stop zoom for eyepiece.

Update: Televue NP101is will also support 35mm chip as will a Vixen VC200L Cassegrain

[RikM]

Before you do anything else, if you want to make a start in deep sky astrophotography, buy and read Making Every Photon Count and it could save you from making a costly mistake. Your 'strong photography background' probably won't be an advantage here as there is a great deal you may have to 'unlearn'. As Keith says, you don't want to use barlows or eyepiece projection for deep sky imaging, a reducer would be most welcome as f/7 is on the limit of being too slow. Your money would be much more sensibly used on an autoguider for your mount (an NEQ6 is a fine choice ) the mount is the most important part of any imaging system, and a guider is part of the mount.

You might want to think about a different camera as well. Something with fewer but larger more sensitive pixels that you would be happy to remove the IR filter from to give you more deep red sensitivity.

As to eyepieces, something like the Baader zoom would be fine for the kids to look through.

[knobby]

Excellent reply Rik...

Couldn't help but chuckle at the last line though...

just picturing Mr Baader and his design team reading ' the Baader zoom should be fine for the kids to look through '