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markclaire50

C9. 25 - opinions

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Just to add my comments in response to your question Mark. When I had my C925 the planets were not particularly well positioned so I don't think I had a fair crack at them. I had a few cracking views of M42 from dark sites with it but don't honestly remember E and F jumping out at me. As we have already covered, seeing conditions make a big impact, probably as much as any other factor.

I did directly compare my Tak FC-100DC with a C8 Edge on Jupiter. The Tak cut through the seeing conditions better and generally presented a fairly stable image with plenty of detail. Colours were there but generally quite muted. The C8 gave more detailed image due to the higher resolution and with more distinct colour, but the views were less stable due to variable seeing ie I had to wait longer for the moments when the atmosphere steadied enough for the views to be crisp. This is a fairly standard example of the balance of resolution vs ability to cut through poorer seeing.

The C925 is optically the best design of all the Celestron SCTs I believe because it has a slightly slower primary mirror which is easier to make accurately. The 925 is longer than you would expect as a result but still very compact for the aperture. Collimation is critical for these scopes to give their best high power views.

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1 hour ago, markclaire50 said:

Hi

Do you have any problems with seeing the E and F stars in the trapezium using your C9.25? 

Cheers

Mark

 

Can see those easily.

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1 minute ago, kirkster501 said:

Can see those easily.

Very interesting. Seems like different people can and others can't with this scope. I'm particularly interested in your opinion because I live not far from Radcliffe so I assume my seeing conditions would be similar. What do you think about chances of getting a lemon if bought secondhand? Would you advise new? 

Very useful info. Thanks! ?

Mark 

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I worry a bit when I see scope decisions based on the achivement (or not) of a very specific observational challenge.

Ten members here could say that they can easily see E & F Trapezium with a certain scope, then you get one, and can't make them out. I'm not sure where that has got you ? :dontknow:

 

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1 minute ago, John said:

I worry a bit when I see scope decisions based on the achivement (or not) of very specific observational challenges.

Ten members here could say that they can easily see E & F Trapezium with a certain scope, then you get one, and can't make them out. I'm not sure where that has got you ? :dontknow:

 

Hi John. No scope decision will be made by me without a very thorough analysis of many peoples experiences on objects in the categories I'm interested in. In the end the decision would be based on balance of probability based on members comments, review articles, theory and any other factors like portability and likelihood of actually getting the scope out and using it. ?

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You already have a Skywatcher 127mm mak-cassegrain don't you ?

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2 minutes ago, John said:

You already have a Skywatcher 127mm mak-cassegrain don't you ?

Yes, and like many members, I'd like a scope with more aperture, as I think the 127mm mak is restrictive compared to 8-9 inch aperture. I certainly feel this is so on objects I have tried to see recently. Hence I am now researching, as many amateurs do, for the best upgrade, within my financial means, to facilitate this. I don't want, nor can afford to, make a mistake in such upgrade. In my experience, taking an average of people's experiences often gives the most accurate idea of the correct decision, which is why I'm gathering as much information as possible. Did you go through a similar process of consideration before upgrading to your Vx12? ?

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16 minutes ago, markclaire50 said:

Yes, and like many members, I'd like a scope with more aperture, as I think the 127mm mak is restrictive compared to 8-9 inch aperture. I certainly feel this is so on objects I have tried to see recently. Hence I am now researching, as many amateurs do, for the best upgrade, within my financial means, to facilitate this. I don't want, nor can afford to, make a mistake in such upgrade. In my experience, taking an average of people's experiences often gives the most accurate idea of the correct decision, which is why I'm gathering as much information as possible. Did you go through a similar process of consideration before upgrading to your Vx12? ?

Hi John. Perhaps I should also say my purchase of the mak secondhand at £160 seemed too good to miss, and I don't regret it. I guess that the higher the potential cost, the more analysis I feel I need to do. But I'd like to feel the next scope would the last. But seeing members collections on this forum, I fear it may not be.... ??

Edited by markclaire50

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54 minutes ago, John said:

I worry a bit when I see scope decisions based on the achivement (or not) of a very specific observational challenge.

Ten members here could say that they can easily see E & F Trapezium with a certain scope, then you get one, and can't make them out. I'm not sure where that has got you ? :dontknow:

 

I'm intrigued by this as well. I have a very dark sky, sometimes reaching SQM22, but the seeing is predictably variable. I have never found E and F 'easy' though this may be me. I'm not a double or multiple specialist. Sometimes I'd call E reasonably easy but never F. Possible but not easy. I've used 10 and 14 inch SCTs, 20 inch Newt, TEC 140 apo, and F has never been 'easy' for me.

Olly

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Lifetime scope ? - we have all been there, several times ! :smiley:

You already have a great scope so you can hone your skills on that (ie: E & F Trapezium) so the next one you get, you will really hit the ground running, so to speak !

Good luck in finding the one for you :smiley:

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6 minutes ago, John said:

Lifetime scope ? - we have all been there, several times ! :smiley:

You already have a great scope so you can hone your skills on that (ie: E & F Trapezium) so the next one you get, you will really hit the ground running, so to speak !

Good luck in finding the one for you :smiley:

Thanks John. I've not given up with the mak, but I'm not sure it'll pick out the F star, looking at Olly's post above! ??

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7 minutes ago, markclaire50 said:

Thanks John. I've not given up with the mak, but I'm not sure it'll pick out the F star, looking at Olly's post above! ??

What can I say ?

I get E &F consistently with my ED120 refractor, E consistently with my 100 / 102 refractors and F on really good nights with those smaller instruments. My observing experience is probably less than Olly's and my skies undoubtedly worse.

But thats just me with my eye from my back yard in a semi-urban environment :dontknow:

"Your mileage may vary" as they say :smiley:

 

 

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I have been in a similar dilemma. I saw an advert for a C11 for <£1000 on UKAB&S not far from my home a few days ago. I mentioned this to a couple of members at my local society open day, (which was earlier today), and was told, "...As much it is a bigger aperture then you C6, you are not going to gain anymore. Stick with what you have. Plus you would need to upgrade your mounts too!" - So the morale is, don't rush into things without considering the financial expense for other things. 

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Strange how some people find things more difficult than others. I'd rate E & F as very easy in the C9.25. I used to pick them up in the 140 Mak too. This is with poor suburban skies.

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1 hour ago, John said:

What can I say ?

I get E &F consistently with my ED120 refractor, E consistently with my 100 / 102 refractors and F on really good nights with those smaller instruments. My observing experience is probably less than Olly's and my skies undoubtedly worse.

But thats just me with my eye from my back yard in a semi-urban environment :dontknow:

"Your mileage may vary" as they say :smiley:

 

 

There seems to be a very large variation on this. I noticed this when looking at Internet reports from different forums, which seem to reflect both yours and Olly's experiences. I think it's confusing to newbies like me. ?

I  can only conclude that differences in location is responsible? I've seen reports of people seeing the stars in very light polluted areas, and others failing in dark skies. AND vice versa! With the same type of scope too?! 

I have read above average successes with 4-5 inch fracs though! Perhaps my 127mm can do it, but not if seeing is against me. I've tried on three separate nights at mags ranging  from 65 to over 250, with baader zoom (with and without baader barlow in place) , an altair wave 6mm and a bco 10mm (after reading your good report on this eyepiece). All failed. As a side note the 10mm bco was wonderful on the moon with the mak! Very Sharp and contrasty! 

Do you think the fracs design is giving them the edge over the mak, at the similar apertures? Refractors are renowned for their ability to split stars. Did I mention my first scope I bought was a secondhand sw 80mm ed? I tried seeing the E and f with that, a few days ago using 25-187x with baader w/wo zoom. Again, despite staring for ages at exactly the right place, I detected no sign of either star at any part of that mag range. The a-d stars were pin sharp, apart from above 150x. Plus, the night before, I had seen a mag 10.8 star in same fov as iwamoto, so I know I should see the mag 10.3 e star. But in reality I couldn't. For the record, I never detected iwamoto. 

Thank 

Mark 

 

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E & F are a little different from most multible star splits because, as well as being quite faint and quite close to brighter stars, they are seen against a nebulous field. I feel that this adds to the challenge of seeing them. I've found that getting the magnification "just right" is important as well. I would have thought 150x - 200x with your 127mm mak would have done the job but your seeing may well have been against so pushing them just beyond reach.

Can you see Rigel's companion and the mag 8.8 4th member of Sigma Orionis ? - if so then E & F might be visible using the above magnification range.

 

 

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37 minutes ago, John said:

E & F are a little different from most multible star splits because, as well as being quite faint and quite close to brighter stars, they are seen against a nebulous field. I feel that this adds to the challenge of seeing them. I've found that getting the magnification "just right" is important as well. I would have thought 150x - 200x with your 127mm mak would have done the job but your seeing may well have been against so pushing them just beyond reach.

Can you see Rigel's companion and the mag 8.8 4th member of Sigma Orionis ? - if so then E & F might be visible using the above magnification range.

 

 

Hi John 

I have also been theorising that the  glow of the nebulosity might be combining with other factors to tip the scales against me. On my very first outing with both my 80mm and 127mak, I found Rigel B an easy target, i.e. I knew it was a double but didn't know where rigel b was, but the 80mm picked it out, and I confirmed it was the right place later. I was very pleased when I saw it for the first time with the 80ed with my baader zoom ( a superb piece of kit, I have found). Every time I've looked at rigel I can clearly see its companion in both scopes. Not tried the 4th member of sigma orion is yet. But it's on my list now. ?

It seems to me from what you say, that I need to keep trying at 150x in the mak. Beyond that I do start to get some star bloating though, but the sky also gets darker which might help. When I first got the mak, I looked at sirius and went out of focus in both directions to check collimation. I saw a perfect set of symmetrical concentric circles. Very pleased as I believe that means it is well collimated: being secondhand, I was slightly apprehensive. Perhaps I will use the 10mm BCO again, w/wo the 1.5x gso barlow to get 150 and 225x mags and keep looking. 

Do you think a filter to cut out the nebulosity might help? 

Thanks 

Mark

 

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I've not found that a filter (of any type) helps because it dims the stars. I have heard that a green or red filter can help with Sirius but I have not found that myself.

 

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On 23/02/2019 at 23:44, John said:

 

 

On 23/02/2019 at 18:55, markclaire50 said:

Hi John. Perhaps I should also say my purchase of the mak secondhand at £160 seemed too good to miss, and I don't regret it. I guess that the higher the potential cost, the more analysis I feel I need to do. But I'd like to feel the next scope would the last. But seeing members collections on this forum, I fear it may not be.... ??

You may end up going through a number of scopes but that can be fun in itself and doesn't have to be expensive if you stick to second hand and don't buy things on impulse.

Regarding the wide variety of experiences being able to see targets such as E and F on the trapezium, I can say that over time I've got used to reading reports by other SGLers and I know how much more or less other individuals usually see compared to me. This is handy for knowing what is and isn't a good target to try for.

The variation as has been said is down to many things, I know that for me I often can't see as much as is shared in observation posts for an accumulation of different reasons.

Edited by Paz

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