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MikeWilson

Gemini Cygni (Sadr) in Cygnus. First light of ED80T CF. Night sixteen.

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Well here we are. Several months on and absolutely no real telescope time under the stars to speak of for me. It's also the anniversary of exactly one year in the hobby of astrophotography. One year and exactly sixteen nights imaging. Not a good ratio when you think about it.

I've gone through a Skywatcher 150P, ST80, Quattro 8" CF and two sets of Binoculars and have finally settled on my new gear.

An Orion ED80T CF, Televue TRF-2008, Starlight Express 2" USB filterwheel, a 9x50 finder-guider and a QHY8L on the back of it. Perhaps I should post a proper review at another time and place but this is my first light and I'd like to show it to you all.

The 18th September was a night with lots of fast moving low level cloud which was mostly passing over Ursa Major so there was absolutely no chance of imaging M101 although I did try - PHD wouldn't calibrate. The finder-guider of mine takes about fifteen minutes to calibrate and any cloud passing over it during this time stands a good chance of killing any calibration so it wasn't to be.

Cygnus was right overhead and relatively cloud free, so I managed to acquire 10x5 minute subs with fairly decent tracking.

6167436585_38ae9cfa68.jpg

Sadr - Star and Nebulosity in Milky Way (10x300s) (18-09-2011)-Stacked-Complete by MikeWPhotos, on Flickr

It's probably worth pointing out that when we moved into our house there was only a streetlight to contend with. During this imaging night I had the usual gamut of around 20 streetlights (all with line of sight into the telescope area), a multistory car park (with bright green and white lights) and a fake air traffic control tower (nobody's at home but the lights are on) and our neighbour opposite has a security light on all day and night and they're not even at home.

That gave this gradient:

post-18683-133877663995_thumb.jpg

What was interesting was that the gradient was only visible in the blue and green channel. So I took those channels, duplicated them (seperately) and applied a dust and scratches filter to blur them out and subtracted them from their respective layers before putting them back together with the untouched red channel. This gives a slightly overprocessed look to this urban deep sky first light but it did generally work.

The other issue that this image has is some coma on the top right and bottom left (this is a 90% crop). I suspect that the focuser isn't holding the TRF-2008 properly or (more likely) that I didn't go around and tighten the compression rings equally. One may have been tighter than the others leading to a slight misalignment of the reducer/flattener in the focuser. I'm going to see if applying some scotch tape to the barrel of the TRF-2008 will allow it to fit more squarely. I'll also take more care next time to tighten the three compression ring screws as evenly as possible.

Thanks for reading! :-)

Clear skies to everyone,

Mike

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And if anyone's interested, this is the uncropped image WITHOUT FLATS to show vignetting.

post-18683-133877664005_thumb.jpg

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It's looking good Mike, just get that reducer square so we can have a better picture of the corners...

You must feel quite relieved after that fiasco with your quattro that youve got some time out !

Nadeem.

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Very good indeed, Mike, and quite a triumph from your impossible-sounding location! I don't feel the image looks over processed, I like the 'look' of it very much.

Yet again the ED80 proves to be the weapon of choice and a true giant killer. I have never owned one but they appear regularly at my place and never fail to amaze.

I haven't followed your Quattro experiences. Is there a thread somewhere that might allow me to catch up?

Again, lovely result and you are a tweak away from a near perfect imaging rig.

Olly

Edited by ollypenrice

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Thanks everyone - you're all far too kind. I prefer a more natural look although I'm really chuffed as I can see the potential here if I can get darker skies (I can :)) and longer subs. I'm a little concerned about the reducer/flattener being seated correctly but we'll see :)

Olly - this probably isn't the ED80 that you're thinking of. This one's the triplet made by Orion USA:

post-18683-133877664013_thumb.jpg

post-18683-133877664022_thumb.jpg

All the best,

Mike

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Beautiful scope Mike, I like it !

How often do you have to change the desiccant on the camera ?

Nadeem.

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I really like this Mike and to have produced it under such poor conditions is amazing. The version without flats is shocking! I also agree with Olly that it doesn't look over processed at all. Quite beautiful.

Mark

P.S. If you get the chance a full review of your gear would be great. :)

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Mike, I think you've done absolute wonders with the processing here, seeing just how challenging the original uncropped image was & the conditions you're trying to image under. As you & others suggest - I think it would be very beneficial for you to write a review/summary of your experiences over the last 12 months, starting up in astro-imaging, what you learnt and where you've ended up. I'm also 3 months into this "journey" and all I can say is that I'm absolutely delighted that I committed up front with a 102mm refractor rather than going for an SCT (which was my initial thinking) or a big bulky Newtonian.

Your Orion ED80 CF is a fantastic scope, being a triplet as well, and should be high on the list of other beginners starting out and is suited also to the experienced user as well. Keep the good work going and the posts, they make good & informative reading.

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Mike,

An encouraging start with the Orion ED80. I am especially pleased as I feel responsible for recommending it to you!

That gradient is the sort of thing Pixinsight's DBE would work wonders on I reckon.

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Ah, thanks for the clarification, Mike. I thought it was the Orion version of the SW. Whatever it is it looks as if you're going to have a ball with it. If I had to keep only one imaging scope it would be my 85mm. Lots to go at!

Olly

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Whoa, that's a pretty cool gradient! :rolleyes:. Anyway Mike, hope your having fun with your new scope - it looks like a real beauty. Looking forward to seeing the images you get with it :glasses2:.

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@Deneb: Thanks - I'm glad you approve :glasses2: Thanks for taking the time to help me with my refractor-related decision making. Regarding the dessicant (that's the silver tube that you can see in the picture) - I applied it after the first light earlier this year and haven't changed it since. This dessicant changes colour as it absorbs water and it hasn't changed, it's still good. My first light with the QHY8L was an image of M13 and all the stars came out looking somewhat diseased. It's hard to describe although I now know what caused it - frost forming on the outside of the sensor window. I was cooling the camera to -25 and Bern at Modern Astronomy suggested that I run the camera warmer. I don't want to do this so I was using a 2" dew strap around the front of the camera to keep dew/frost off the sensor window. It works and now I've since upgraded to a dedicated ~6mm heated ring which you can see in the picture. I've since soldered this to a dew heater for the finderscope and the two are left permanently attached to this rig.

@Mark: The version without flats is a little nuts, isn't it? I don't honestly know where all that dust comes from. The CCD looks clean so it might be in the filter wheel. I'm really not sure how to get rid of it - I have a blower but wouldn't that just blow the dust somewhere else? As for vignetting - the Quattro 8" CF was better, illuminating the whole APS-C sized frame whereas this (even with a 3" focuser) does vignette a little bit. Not a problem with flats of course.

@Martin-Devon: A review post would be a really good idea. I will combine it with a review of the scope, I think. The 100-120 sized refractors do look the business although if you're purely visual I think there's a lot to be said for the SCT. I miss my Mak 127 - with over a meter of focal length and 5" (partially obstructed) of aperture it was a real killer on the planets. It gave me my first view of Jupiter last July and I was bowled over. Couldn't find anything on the silly GPS so I pointed the scope at the brightest dot in the sky and was quite literally floored by the view. I even video'ed my first reaction to something through an eyepiece but I don't think I'll ever publish that video!

@John: Without your recommendation I wouldn't have had the Orion ED80T CF on the list. Although ultimately all these scopes are sourced from the same small set of niche far-eastern suppliers, the Orion scopes weren't my first choice. For me it was between the ED80/Equinox80 and the GT81. Not because I wanted a 'cheap' triplet but my main criteria was for a small quality scope that also had a Synta hotshoe as my guiding mechanism was based on a finder scope. It's not quite as quick to calibrate as the ST80 but I've had it guiding at 800mm focal length so with this scope at <400mm, the finder guider does the trick comfortably. Ideal for me as I have to be portable.

@Olly: "Whatever it is" made me laugh out loud! Last month I had no idea this scope even existed and it was John's recent acquisition that piqued my interest. I dare say that this scope feels very high quality - having handled an Equinox 80, I'd say that the fittings feel as good if not better than the Equinox 80. There are some cosmetic imperfections in the carbon fiber resin though and I'm a little concerned that the dew shield (lovely and long when extended) retention screw might scratch the beautiful scope finish but the scope is very high quality indeed! The focuser is a delight to use even with all the weight hanging off it but a minor complaint - the compression ring is smaller than the compression ring cut-out on the TRF-2008 so I'm going to need to apply a little scotch tape or something (or maybe some ring/threaded adapter as the focuser appears to have a female thread in it - quite large, maybe approximately SCT sized.

@Andy: Thanks for admiring the gradient! It is a little crazy and I was super fortunate to have it only present in the green and blue channels. It is present in the red but you can't really detect it. In processing the image I did lose some of the detail around the star shapes - Sadr for instance looks a little washed out rather than the perfectly formed smooth star that it was.

Thanks everyone for your helpful and encouraging comments. Critical comments are also welcomed - but yes, I'm delighted with this first light image! So delighted that I sent it in to S@N hotshots. I'm not expecting anything but it felt good sending the email nevertheless!

All the best,

Mike

Edited by MikeWilson
added paragraph on QHY8L dessicant for Nadeem.

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Mike,

I was worried about the screw on the "looooooooooong" dew shield too - but it's on a compression ring to stop it scratching the OTA surface.

I haven't been able to find a single blemish at all on mine!

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Thanks Earl :glasses2:

Hi John - that compression ring is good news. I also note that you used ST80 rings on yours. I fitted rings to mine too before I noticed that the shoe is very stiff and balances perfectly :-)

As for blemishes - I have a couple but they're very minor. The resin on the CF is very slightly raised on one small area and if you look closely you can see some glue holding the front objective on. But the overall quality does feel pretty spot on.

How did you find the focuser compression ring? Does it hold your reducer/flatener square?

Clear skies,

Mike

Sent from my mobile using TapaTalk (so please excuse bad grammar & spelling!) :-)

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Mike are there any openings on your filter wheel that could cause light ingress? I had gradients like this and it was caused by the filter wheel.

Edited by shaunster

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Hi Shaunster,

I don't think so, but I can check by putting the lens cover on and taking darks to test.

All the best,

Mike

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Oops, topic needs renaming! Thanks PB!

Sent from my mobile using TapaTalk (so please excuse bad grammar & spelling!) :-)

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