Baader RCCI Rowe Coma Corrector, so far not impressed

[ultranova]

Hi Every one, I am after some advice if possible, I have something funky going on with my latest purchase the Baader Rccl Rowe coma corrector.

my scope is a Quattro f4 cf. I Image with a canon SLR and have been using the MPPC corrector , I knew the MPPC might struggle a little to get the stars looking better in the corners being just outside its optimal range.

So as you do I saved up and got this particular corrector from The good people at FLO for two reasons.

1/ in the future I might fancy some off axis guiding 2/ it should do a better job at correcting the f4 newt as it supposed to correct down to f3.5, F4 being the optimum for the corrector.

So last night was the first night in getting to use it, it was a star test more than a full blown image capture. as I knew the clouds were about so any image time with the new kit would be a bonus.

I was a bit concerned at the results, there appears to be rotational coma in the corners not the usual star trailing towards the centre, I am a bit confused as i have never seen this before.

I am having to sink the whole corrector into the 2 inch holder on the scope, as with the stopper ring attached I can not get focus.

so the only thing i can think of is the corrector being so far down the tube is messing up the light cone before it gets to the camera chip.

Or is it the corrector is Pants.

Any help or advice would be much appreciated

I have attached two pics one taken with the MPPC the other with the RCCl

[ultranova]

Hi every one, sorry forgot to mention the pictures show a 150 x 150 pixel square of each corner of the original photo,

with the centre 150x 150 pixel in the middle, all at 100% size of the original

On both of the photos from which these were taken, the middle out to around 70% of the picture the stars are ok.

[Earl]

What are the spacing requirements for the cc

[ultranova]

Hi its 91.5 mm to chip, i can get the quite accuratley by using the baader varilock t-2 extention,

As shown in photo.

Just seems a very odd coma ,circular ?, I was hoping taht some one might be able to tell me what the problem is.

Im stumped on this one

[RikM]

I had something that looked like that when my polar alignment was out. I was guiding fine in the centre of the field but ended up with rotational smearing at the edges. There is no chance anything has slipped on your mount? In my case it turned out that I had used the wrong scale on the RA ring when calibrating the reticule

[ultranova]

There is always that possibility, did not think of that one, as far as I know everything was tight, and polar alignment was about normal,

But it is possible that something moved , I am going to give it a few more tries as soon as the clouds disperse and the moon disappears and the wind drops and everything else that's required LOL

[appyaardvark]

Sorry, I know this is an old post, but I may need to purchase one of these correctors, as I have the Atik OAG. Did you get satisfactory results, after adjustments?

[ultranova]

On ‎26‎/‎01‎/‎2017 at 12:23, appyaardvark said:

Sorry, I know this is an old post, but I may need to purchase one of these correctors, as I have the Atik OAG. Did you get satisfactory results, after adjustments?

Never was happy with the results in the end I stuck with my mppc

[SubOptimal]

On 8/29/2012 at 13:17, ultranova said:

Hi Every one, I am after some advice if possible, I have something funky going on with my latest purchase the Baader Rccl Rowe coma corrector.

my scope is a Quattro f4 cf. I Image with a canon SLR and have been using the MPPC corrector , I knew the MPPC might struggle a little to get the stars looking better in the corners being just outside its optimal range.

So as you do I saved up and got this particular corrector from The good people at FLO for two reasons.

1/ in the future I might fancy some off axis guiding 2/ it should do a better job at correcting the f4 newt as it supposed to correct down to f3.5, F4 being the optimum for the corrector.

So last night was the first night in getting to use it, it was a star test more than a full blown image capture. as I knew the clouds were about so any image time with the new kit would be a bonus.

I was a bit concerned at the results, there appears to be rotational coma in the corners not the usual star trailing towards the centre, I am a bit confused as i have never seen this before.

I am having to sink the whole corrector into the 2 inch holder on the scope, as with the stopper ring attached I can not get focus.

so the only thing i can think of is the corrector being so far down the tube is messing up the light cone before it gets to the camera chip.

Or is it the corrector is Pants.

Any help or advice would be much appreciated

I have attached two pics one taken with the MPPC the other with the RCCl

In your images: the MPCC radial smearing looks to me like it's coma, whereas the RCCI is circumferential looks like it might-be field rotation. But then I'm no expert. I'd really like to know.

[Adam J]

its over correcting your spacing it too long.