Altair Astro 6” Ritchey Chretien review

[ollypenrice]

Thank you for the comments guys, you are making me blush!

Seriously though what would the equivalent 900mm focal length f/6 triplet refractor set you back?

It doesn't exist. Our TEC 140 with 980mm FL at F7 is about 6000 dollars plus the bits. Your point is well made.

Olly

[3ggman]

Fantastic image, I nearly regret having sold my 6"RC but I didnt have the time to put into it.

[Sp@ce_d]

Oh No.. No... it's bad enough trying to decide on a quattro or MN190 as my next scope for the small stuff.. there's no way I can afford a frac.. but now you've really tempted me to consider a RC. Interesting thread and good honest review.. but the M82 speaks for itself!

[Chris Rowland]

I bought one at Astrofest today, it's supposed to arrive in about a week. Not sure if I hope it arrives by the 15th so I can try it for asteroid spotting or later so it's clear for the asteroid.

Chris

[johnrt]

Continuing my experiences with this scope here is an image I have put together with it over the last few days. The 3.5 hours of luminance was shot under great conditions, no moon and decent seeing. The RGB however was taken with at least a 50% illuminated moon and at least One night had lots of moisture and very high thin cloud about. But still, you take what you can get in the UK!!

It adds up to about 8.5 hours - 3.5 in Lum, 2 in Red & Blue and just an hour in green. Same kit as before APCCDT67 tele compressor, Atik 314l+ & Pixinsight / CS5 for the calibration, integration and processing.

Hopefully I'm starting to build up a good idea of the possibilities with this scope for anyone who is considering one.

Edited February 20, 2013 by johnrt

[Gonzo]

Great image, thanks for sharing what can be done with this scope (which I'll defo get one soon)

[Sp@ce_d]

You've really got me thinking of one for the smaller stuff instead of the MN190 or Quattro I was considering. Seems to work well with the 314. How do you find it holds focus throughout the night? I'd be looking at hanging a 314/EFW2 & maybe an OAG off it (if the st80/qhy5 wasn't good enough). I also see you are tempted by a feathertouch for it.

[johnrt]

You've really got me thinking of one for the smaller stuff instead of the MN190 or Quattro I was considering. Seems to work well with the 314. How do you find it holds focus throughout the night? I'd be looking at hanging a 314/EFW2 & maybe an OAG off it (if the st80/qhy5 wasn't good enough). I also see you are tempted by a feathertouch for it.

It holds the focus fine once it is dialled in, but to be honest the focuser supplied isn't great but will do for now. I'll definitely be adding a feather touch from FLO when I can sneak one in past the lady who holds the purse strings.

[ollypenrice]

Nothing to be said. That's a very good image indeed. Really super.

Olly

[r3i]

IMy RC8 is not perfectly collimated at the minute - it is out slightly. I am waiting for a few collimation bits from Howie Glatter before I set out to fine tune it. I don't want to mess this up and get it into an unrecoverable situation. I want to make a tutorial or video when I do this since such info is thin on the ground.

I'll certainly look forward to any feedback you can give on using the Howie Glatter stuff on your RC8. I've so far just used a Cheshire eyepiece to collimate and I seem to get a reasonable collimation but would certainly be interested in any tools that may be able to really nail it down.

[swag72]

I wish I could stop looking at this thread - But I can't!!

My concerns are two fold - Firstly, collimation and then that in order to really nail it you need to spend probably as much as the 6" in order to get it spot on. Madness!!

[kirkster501]

It holds the focus fine once it is dialled in, but to be honest the focuser supplied isn't great but will do for now. I'll definitely be adding a feather touch from FLO when I can sneak one in past the lady who holds the purse strings.

I have the feathertouch of my RC8 and it is very, very nice.

I have yet to use my RC8 in anger yet though. The weather has just been too cloudy for weeks now. I had the RC8 on the mount last night and was doing some plate solving testing with it works brilliantly. Thought i might get my first proper try at M81 but cloud rolled in

My RC8 is not perfectly collimated at the minute - it is out slightly. I am waiting for a few collimation bits from Howie Glatter before I set out to fine tune it. I don't want to mess this up and get it into an unrecoverable situation. I want to make a tutorial or video when I do this since such info is thin on the ground.

The RC8 needs a few extra accessories to get the most out of it I have found. Picture here - look at the dew...

[Gonzo]

I wish I could stop looking at this thread - But I can't!!

My concerns are two fold - Firstly, collimation and then that in order to really nail it you need to spend probably as much as the 6" in order to get it spot on. Madness!!

please elaborate, I'm curious to know.

[swag72]

...... Howie Glatter stuff......... I've so far just used a Cheshire eyepiece to collimate and I seem to get a reasonable collimation but would certainly be interested in any tools that may be able to really nail it down.

Perhaps I am being cynical, but I would be surprised if the Howie Glatter stuff is that cheap and two things were mentioned in the thread up from this one. Then it is stated here that the Cheshire gets a reasonable collimation, suggesting that to really nail it, you need additional 'stuff'

please elaborate, I'm curious to know.

So, lets assume I'm from the camp that wants the collimation 'nailed' and not reasonable - The 6" from AA costs £399 and I bet the goodies to get the collimation spot on aren't far off this price? Or do you think I'm just being cynical about the prices of astro stuff and the niche market

If I'm wrong, I look forward to being corrected - If not it will help me to somehow stop looking at this thread and dreaming!!!

On the other hand - Having never used anything but a refractor, perhaps I'm just getting all this collimation lark wrong as well!

Edited February 20, 2013 by swag72

[Gonzo]

I'm planning to buy the 6"RC myself at some point this year, no idea on how much I need to spend into the collimation gizmos...

[kirkster501]

You don't need to buy anything to collimate a RC other than a cheshire EP. However, some other bits mate it easier in exactly the same way as it does with a Newt or a SCT. If you have only ever owned refractors this may be unfamiliar territory.

I want a precision collimation laser device for a Newt as well that's why it will be very useful for my RC. So am holding out fiddling with the RC until i get that device. Were I not a Newt owner I would stick to the cheshire only.

[swag72]

......................... If you have only ever owned refractors this may be unfamiliar territory...............

Probably understatement of the century. I must return from La La land and stop wishing for a longer focal length!

[kirkster501]

Probably understatement of the century. I must return from La La land and stop wishing for a longer focal length!

Lol, stop being such a wuss and buy a RC Sara! You know it makes sense Go on you know you want to.......

[Sp@ce_d]

Hmm.. a 6" @ f9 or 8" (or bigger) @ f8 reduced to... what.. f6 or f5.5? decisions .. decisions..

Then there's steel or carbon.. does it really make a difference if its in an obsy and has ali bars top and bottom anyway.. surely they will expand & contract?

Aside from the previous mention of collimation extras ( I have the Hotec laser only ever used it on the frac) there's a

reducer which is a must really for AP, the Feather touch upgrade is almost as much as the 6" scope. Probably a focus motor too for remote...

[kirkster501]

I have the CF. looks nice and lighter than steel. But lower expansion and all that is a load of rubbish IMO since top and bottom rail are metal and will expand anyway.

I don't gave a reducer yet. Will see how I get on with it natively before trying one of those. Weather has been so rubbish I have yet to properly use it in four weeks so far! I tested plate solving with it last night and it works brilliantly. Then clouded over.....

Steve

Sent from my iPhone using Tapatalk

[r3i]

So, lets assume I'm from the camp that wants the collimation 'nailed' and not reasonable

Hi Sara,

Perhaps I need to clarify my statement about the Cheshire giving me a reasonable collimation.

I've stated that the Cheshire gives me 'reasonable' collimation because I haven't had the time to properly assess if the collimation is spot on or not, though it does looks OK - Up till now I've had to set up and tear down on each session and with the UK weather the way it is, sessions are few and far between., so I haven't spent ages agonising whether I've squeezed the last drop of collimation out of the scope.

Things are about to change as I'm nearing completion of my observatory so once everything is permanently set up, I will want to start 'nailing' things like collimation, balance, polar alignment etc. etc.. The Cheshire alone may yet prove to be sufficient once I've spent the time and effort on properly checking my collimation. I'm not planning on investing in the Howie Glatter 'stuff' but I'm still interested in knowing how effective a tool it may be.

[Jessun]

Fine review and excellent results John!

I think CF is just in fashion basically, it pops up everywhere these days. The Alu bars will do their thermal movements anyways. On the other hand the non CF versions have a steel tube - and Alu expands twice as much as steel, so no immediate gain there really. It comes down to that last pound of weight or so, and wether you like black CF or white paint...

A coupling between the bars and the tube that allowed differential expansion could be a money maker for the first company to sell them.

I have the 8" steel but am thinking of moving up to 10" in order to keep the same FL roughly - which I quite like - but at f5.4 instead of f8. Collimation is not second nature to me, but quite a few ouf you RC guys seem to have it nailed. May just ask one day how you did it...

/Jesper

[kirkster501]

Thisis a good thread where jjongmans talks about his method.

This is also a good commentary

There are guides out there on the net.

I don't think the RC is any more difficult than any other type of reflector - its just there is not as much info or experience out there about them. I am also somewhat ignorant though have had a bit of a play and it seems straightforward enough. However, I am not perfectly colimated as yet so going to have a play around with a holographic laser and compare the cheshire to the results I get from the laser. No point in messing it up into a unrecoverable situation until I have a more accurate tool to get me back. I will then write an idiots guide to this,

[Jessun]

You sure have done the homework! Cheers for the links!

/Jesper

[swag72]

Good link to that commentary, I think your job is done, I shall be leaving an RC well alone. Now to take it off my CCDCalc before I forget what I've just read and think that it would all be OK.