The "No EQ" DSO Challenge!

[SteveNickolls]

That's come out very nicely indeed Nige the Bubble Nebula is shown very well. Dark background too. Look forward to NGC 7000. I also admire your fortitude imaging so late, 'erm I mean so early :-) The large size of your objective certainly pulls in the photons.

Cheers,

Steve

[The Admiral]

Nice one Nige.

I went out last night for the first time in ages; the sky seemed beautifully clear but it was rather breezy. My aim really was to visually observe Saturn, though I did try to image it as well. I can't say it was entirely successful as I don't have a lot of magnification available with prime focus imaging, even though I used a 2X extender, and what with it being so low down. It did cross my mind to try a spot of DS imaging as well, but when I tried a frame it was clear it was by no means sufficiently dark. I don't have the staying power for the early morning imaging that you do. But as you say, even that is curtailed at this time of year.

Ian

[happy-kat]

Are you not tempted to do just one image so you get more data now that we are in summer?

[Nigel G]

31 minutes ago, happy-kat said:

Are you not tempted to do just one image so you get more data now that we are in summer?

I'm planning to add to the images, the first image is with the street lights on, I'm trying to get NGC 7000 after 1am to loose the street light pollution, that gives me a max of 2 hours before its too light. 

Nige 

[Nigel G]

Thanks guys. 

Next image I'm very pleased with considering the relatively short exposure time.

Field rotation was getting quicker as I was taking these,  by 3 am the scope was very close to touching the tripod at a high altitude and the sun was getting closer  . With the strong breeze, maximum exposure was 45s after a hour or so only 30s was possible, 50% I had to delete .

Even so my patience paid off I think. 

Nige. 

NGC 7000 part 2. 55x45s and 20 x 30s light, 12 x 45s and 12x30s dark, flat and bias. Star discovery 150p, Canon 1200d, DSS and StarTools. 

[SteveNickolls]

I do like your latest image very much Nige, lots of detail and good colours. You should be very pleased  how it has come out :-)

Cheers,

Steve.

[The Admiral]

That's come out rather well Nige, the nebulosity is nicely defined. Looking up the specifics,I see that by 03.00 it is at an elevation of 80° and almost due south, at which your exposure time needs to be around 5s to keep field rotation in check! You certainly are pushing the envelope.

NGC7000 is a huge object. Are you planning to do a mosaic?

Ian

PS. Ah I see that in the past you posted images of different parts of NGC7000. I'm losing your plot here!

PS2. I take it you managed to get your sensor clean without problem?

Edited July 2, 2016 by The Admiral

[Nigel G]

3 hours ago, The Admiral said:

That's come out rather well Nige, the nebulosity is nicely defined. Looking up the specifics,I see that by 03.00 it is at an elevation of 80° and almost due south, at which your exposure time needs to be around 5s to keep field rotation in check! You certainly are pushing the envelope.

NGC7000 is a huge object. Are you planning to do a mosaic?

Ian

PS. Ah I see that in the past you posted images of different parts of NGC7000. I'm losing your plot here!

PS2. I take it you managed to get your sensor clean without problem?

Ian, I am planning to do a mosaic image but have no idea where to start, what software to use etc, to be honest I haven't started researching yet.

The sensor needed a light brush with wire wool ☺..... a sensor brush ☺job done .

Nige.

[Nigel G]

Well after a tough night thinking about light speed and distances and trying to understand our Universe ☺ ( you'll know what I  mean if you saw last  night's post.) During which the clouds were beginning to clear I managed to get just over 30 minutes of subs before the cloud became to much on a target I've been waiting for since I began imaging. 

Seeing was quite poor with light cloud passing randomly but I was being impatient, the fact is the object is in a prime position for imaging now and I'm  away for 4 weeks next weekend. Plus a whiskey or 2 gave me a bit of stamina. 

This needs longer time on during good conditions and will get it eventually. 

Also I had a quick try at imaging M27 with a barlow but quickly gave up,,,,,, tracking and exposure needed is behond the capability of my mount ☺. Good thing is it only took a few minutes to work that out. 

M 31 Andromida galaxy less that 13.7 billion light years away. 40 x 45s at 1600 iso  light, 10 dark and flat plus bias. Star discovery 150p canon 1200d. DSS and StarTools.  Poor seeing.

Nige.

[SilverAstro]

1 hour ago, Nigel G said:

Well after a tough night thinking about light speed and distances and trying to understand our Universe ☺ ( you'll know what I  mean if you saw last  night's post.) I dont remember you submitting a proposal to the committee to go and do some actual astronomy !!! would you believe whatever next

 

Quote

tracking and exposure needed is behond the capability of my mount ☺. Good thing is it only took a few minutes to work that out. Quicker than sorting out the big bang !

M 31 Andromida galaxy less that 13.7 billion light years away. Prove it

 

 nice one, glad we kept you awake long enough to catch the clear sky,(I thought it went quiet !!),  good start there and yes you deffo need the cut-down focus tube and no barlow for that one, it'll be good to watch how you get on with this target,

thanks for showing. (and the late night conversation !)

Edited July 9, 2016 by SilverAstro

[Nigel G]

Just run it through photo shop express to adjust exposure and contrast,  I will re process this later as it was rushed by an impatient me at 3am ?

[Nigel G]

3 minutes ago, SilverAstro said:

 

 

 nice one, glad we kept you awake long enough to catch the clear sky,(I thought it went quiet !!),  good start there and yes you deffo need the cut-down focus tube and no barlow for that one, it'll be good to watch how you get on with this target,

thanks for showing. (and the late night conversation !)

Ha ha ha ?nice, and thanks ☺I must read through the universe post when I get home later, and see if I can prove M31 is less than 13 billion ly away ☺

[Chinapig]

Hi folks

Just discovered this thread - fascinating stuff, and pretty damn inspiring!  I do have an EQ mount (AZ-EQ6), but often leave it in alt-az mode for purely visual, particularly so I can hang a couple of scopes on it for outreach events.  I've yet to try imaging with it in alt-az, but am now inspired to give it a go.

 

Just come back from a short break in the Canaries, staying on the south side La Gomera.  Amazed at the sights available that you can't see from the UK, especially Omega Centauri, which blew me away even just through my wee 8x42s.  Wished I'd taken a scope.  And also wished I'd taken a tripod!  I hope this image is valid for this thread - I wasn't using an EQ mount, not even a tripod, simply an Olympus EM-5 micro four-thirds camera, propped up on a couple of cushions, on the balcony table.  Framing was therefore a bit of a challenge!  Here's a single 30-second frame, at ISO5000.  As grainy as Brighton beach, but hey - you can see the Milky Way, with Mars and Saturn in the frame (Mars isthe brightest object at top right).  Can't wait to go back, armed with a small scope + tripod, and try some multiple short exposures.

 

Cheers all

[Nigel G]

Nice,  that definitely qualifies 

imagine what a scope could see ☺. If only we had good dark sky's around here.

Thanks for sharing 

Nige.

[Nigel G]

Just seeking people's opinions ,  Star travel 120 refractor  or  130p-ds reflector for imaging on alt az. Both F5 scopes. 

I'm interested and still un decided,  would love to fork out on a triplet refractor but not enough funds.

Nige.

[happy-kat]

The 130p-ds is a given performer. I have seen a stunning narrow band image from the ST120 but you will have CA to process out and you could have other lens abberations as well. But adding a field flattner to the p-ds makes the cost shoot up. Decisions. What about your target choices and imaging camera how does the fov compare. Both weigh 4 kilos. Refraction spikes or none.

Edited July 11, 2016 by happy-kat

[Stub Mandrel]

4 hours ago, Nigel G said:

Just seeking people's opinions ,  Star travel 120 refractor  or  130p-ds reflector for imaging on alt az. Both F5 scopes.

Look at the threads showcasing the 130P-DS and the 'no-eq challenge' and I think that becomes a no-brainer :-)

[Nigel G]

4 hours ago, happy-kat said:

The 130p-ds is a given performer. I have seen a stunning narrow band image from the ST120 but you will have CA to process out and you could have other lens abberations as well. But adding a field flattner to the p-ds makes the cost shoot up. 

I'm afraid I don't know anything about flattners or where to put them or CA, need to research a bit.

 

[Herzy]

17 minutes ago, Nigel G said:

I'm afraid I don't know anything about flattners or where to put them or CA, need to research a bit.

 

Field flatteners go in your scope's focuser and fix the oblong stars in the corners/edges of images. CA is something specific to achromatic refractors. It's strange color fringing around bright objects that is especially distracting in astroimages. APO refractors were designed to remove this problem by focusing all wavelengths of light in the same place though a series of lenses. Newtonians don't have CA because they don't use lenses.

There is a quick rundown, hope it helps!

[Nigel G]

1 hour ago, Herzy said:

 

There is a quick rundown, hope it helps!

Herzy,  thanks for explaining,  that helps a lot ☺

Nige.

[SilverAstro]

1 hour ago, Nigel G said:

or CA, need to research a bit.

CA = chromatic aberration, is what happens in the glass of a lens, like in a prism, and gives the colour fringing that Herzy describes. Does not happen on the aluminium surface of a reflector

an Achromat (achromatic) lens attempts to correct this CA for a limited selection of colours by using lens elements made of different refractive indexes.

an APO = apochromat (apochromatic) lens, corrects CA for a wider selection of colours by using even more lens elements of even fancier design and thus more expensive than an achromat.

The chromatic problems of lenses (refractors) are reduced when imaging through monochromatic filters with monochrome cameras.

hth

 

 

[happy-kat]

But then you rely on the quality of the lens to not introduce other abberations in the lens. The startravel refractors are not aimed at being perfect and might show other imaging issues. Luck of the draw. I will see if tomorrow I can find the post that talks about this.

[Nigel G]

Thanks for your replies, I'm learning ☺

I'm thinking the 130p-ds, do you think I would be wise to get a coma corrector and can I use a coma corrector with a dslr? 

Will a coma corrector be of benefit when using an alt az mount .

So many questions,  maybe not the right place to post but as it's for use on the alt az mount imaging dso's this seems the right place, 

Nige.

[Herzy]

1 hour ago, Nigel G said:

Thanks for your replies, I'm learning ☺

I'm thinking the 130p-ds, do you think I would be wise to get a coma corrector and can I use a coma corrector with a dslr? 

Will a coma corrector be of benefit when using an alt az mount .

So many questions,  maybe not the right place to post but as it's for use on the alt az mount imaging dso's this seems the right place, 

Nige.

A coma corrector will work regardless of the mount. It just fixes the elongated stars. I don't have one atm because I'm not really annoyed by the strangely shaped stars but most people use one. As for if you should go with a 130p-ds, that is a very nice scope for astrophotography but eventually your going to want an APO refractor. So I would suggest you upgrade to the 130p-ds now and then save up for an APO because they are very good for astrophotography.

[SilverAstro]

I fear I might have lost the plot here ( long day + some amber nectar!) -
but why do you want to downscale from your 150 reflector to a 130 reflector ? ( going to a refractor is a whole other kettle of fishes ! )
In an Alt-Az context duration of exposure, and number thereof, is the (main?) problem so 150 wins over 130 for photons captured. A secondary problem is the stability of the mount vs. size of scope but you have already proven that is OK for your 150.
Another prob might be the focuser (DS vs not DS) but again you have that sorted !
The 130P-DS (if it is like the 150P-DS) has the secondary closer to the primary for photography at prime focus, but you sorted that with your hacksaw.

Another prob is criticality of collimation at f5 of the fixed 150 vs the adjustable 130, but you sorted that by un-fixing the 150 !

So I am not seeing why you want to go down to a 130 ?

120 refractors are above my paygrade/competance

 

 

Edited July 12, 2016 by SilverAstro