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I took Olly @ollypenrice seriously when he claimed that 6" refractors are great galaxy hunters, so I let my EdgheHD scopes rest in the cupboard and put the Esprit 150 at work. These images summarizes the few clear night I had in February and March. RGB was collected with ASI071 (OSC) in most cases supplemented with additional lum from ASI 1600 MM (sometimes sitting on the Esprit 100).

Top left: NGC2903

Top middle: NGC4712, 4725, 4747

Top right: NGC3718 and 3729

Bottom: M96 and M96

Yes, I have already posted the images separately, so excuse the spamming but I thought it was nice to see them together. It also gives an idea of their relative sizes as all imgaes are on the same scale.

Comments welcome, including if I should put the 11" EdgeHD on the mount instead.....

 

Galaxies feb-march 2019smallSign2.jpg

Edited by gorann
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4 minutes ago, JeremyS said:

Personally I very much like the wide fields, @gorann. It's nice to see the galaxies set within their accompanying star fields.

Nice work!

 

2 minutes ago, geoflewis said:

Göran , that's an excellent presentation of galaxies. It's great to see them together and each in a wider field context. Cheers, Geof

Thanks Jeremy & Geof! Glad you like the idea.

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21 minutes ago, Firas said:

Great results indeed Göran! That Espirt is really delivering! 

 

Tack Firas!

I saw that you captured an excellent M51 wide field recently with Wim in Vallentuna. Did you get enough RGB to add to it?

Edited by gorann
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I think I did, though much less than the luminance. Calibrating RGB now to make sure. I am trying to find out whether I captured some unknown IFN, but it seems just light astray from the strong Alkaid despite it's more than 2 degrees away!  

 

 

Edited by Firas
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1 hour ago, JeremyS said:

Personally I very much like the wide fields, @gorann. It's nice to see the galaxies set within their accompanying star fields.

Nice work!

I agree, but my argument as mentioned by Goran and published in Astronomy Now magazine in September 2018, didn't just make the case for a wider field of view from the refractor's reduced focal length. I also discussed the fact that I had been unable to extract more genuine galaxy detail from a 14 inch optimized Dall Kirkham than from our TEC140. The longer focal length certainly produced a larger screen 'object image' (and so a narrower FOV on the same sized chip) but what I found in the larger images was 'empty resolution.' That's to say that there was no significant difference in perceptible object detail. Because the data was taken on different nights the test was not entirely rigorous but I think it was valid on a 'real world' basis. 

The imager using the 6 inch (ish) refractor is going to have to make a good job of the small targets because a satisfying presentation will need to be at full size. There will be no hiding behind a 50% presentation!

Goran, I think you have vindicated the '6 inch refractor with small pixel camera' argument pretty clearly here. To be honest I expected the article to generate at least a bit of hostility but this hasn't been so and I've just been approached by a Dutch publication who'd like to translate some of it with Astronomy Now's permission (which has been granted.)  I believe that big refractors and small pixels are on the move! The fact that FLO are offering the Skywatcher Esprit 150 at £3999 (about what I paid for my second hand TEC140 six years ago...) makes it a competitively priced galaxy imaging scope as well as an easy and effective one.

Keep 'em coming!

Olly

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1 hour ago, ollypenrice said:

I agree, but my argument as mentioned by Goran and published in Astronomy Now magazine in September 2018, didn't just make the case for a wider field of view from the refractor's reduced focal length. I also discussed the fact that I had been unable to extract more genuine galaxy detail from a 14 inch optimized Dall Kirkham than from our TEC140. The longer focal length certainly produced a larger screen 'object image' (and so a narrower FOV on the same sized chip) but what I found in the larger images was 'empty resolution.' That's to say that there was no significant difference in perceptible object detail. Because the data was taken on different nights the test was not entirely rigorous but I think it was valid on a 'real world' basis. 

The imager using the 6 inch (ish) refractor is going to have to make a good job of the small targets because a satisfying presentation will need to be at full size. There will be no hiding behind a 50% presentation!

Goran, I think you have vindicated the '6 inch refractor with small pixel camera' argument pretty clearly here. To be honest I expected the article to generate at least a bit of hostility but this hasn't been so and I've just been approached by a Dutch publication who'd like to translate some of it with Astronomy Now's permission (which has been granted.)  I believe that big refractors and small pixels are on the move! The fact that FLO are offering the Skywatcher Esprit 150 at £3999 (about what I paid for my second hand TEC140 six years ago...) makes it a competitively priced galaxy imaging scope as well as an easy and effective one.

Keep 'em coming!

Olly

The most detailed galaxy image I have ever seen from an amateur was of M82 with a 300mm Newtonian and a ASI290mm shooting 2 second exposures at very high gain. I would be interested to see a comparison of that technique on a 6 inch refractor to see if the detail resolved is still comparable to the 300mm scope.  But for traditional imaging you are correct. 

https://www.cloudynights.com/topic/607123-messier-82-newton-3051500-asi290mm-c/

Adam

Edited by Adam J
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1 hour ago, ollypenrice said:

The fact that FLO are offering the Skywatcher Esprit 150 at £3999 (about what I paid for my second hand TEC140 six years ago...) makes it a competitively priced galaxy imaging scope as well as an easy and effective one.

Now we just have to wait for images taken with a SW 150ED and a small pixel camera. That scope is half the price of its Esprit counterpart.

Very nice presentation Göran. The weather hasn't been in your favour this season. :icon_salut: :icon_salut:

Hopefully you get more opportunities after next full moon. Astro season will soon be at an end up here.

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2 hours ago, Adam J said:

The most detailed galaxy image I have ever seen from an amateur was of M82 with a 300mm Newtonian and a ASI290mm shooting 2 second exposures at very high gain. I would be interested to see a comparison of that technique on a 6 inch refractor to see if the detail resolved is still comparable to the 300mm scope.  But for traditional imaging you are correct. 

https://www.cloudynights.com/topic/607123-messier-82-newton-3051500-asi290mm-c/

Adam

Indeed, the 'lucky imaging' fast frame approach to DS imaging is also in the air and may well be a game changer. The image in the link looks only at the bright core so it doesn't tell us anything about the potential for capturing faint signal but I still think that change may not be far away.

Olly

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I’m currently experimenting with an ASI 120 MM on the Esprit 150, with a view to acquiring an ASI 178 or 183 for galaxy imaging as opposed to the Atik 460 or similar. As usual, some clear, moonless darkness would be nice.

5 hours ago, ollypenrice said:

 I believe that big refractors and small pixels are on the move! The fact that FLO are offering the Skywatcher Esprit 150 at £3999 (about what I paid for my second hand TEC140 six years ago...) makes it a competitively priced galaxy imaging scope as well as an easy and effective one.

Keep 'em coming!

Olly

Olly, It’s by no means a scientific survey but I noted with interest that truss tube RCs were very thin on the ground at the Practical Astronomy show last weekend, while larger refractors were in abundance. This was in stark contrast to 4 years ago when RCs were on prominent display at the IAS. I am also sensing a shift in the established thinking.

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1 hour ago, tomato said:

I’m currently experimenting with an ASI 120 MM on the Esprit 150, with a view to acquiring an ASI 178 or 183 for galaxy imaging as opposed to the Atik 460 or similar. As usual, some clear, moonless darkness would be nice.

Olly, It’s by no means a scientific survey but I noted with interest that truss tube RCs were very thin on the ground at the Practical Astronomy show last weekend, while larger refractors were in abundance. This was in stark contrast to 4 years ago when RCs were on prominent display at the IAS. I am also sensing a shift in the established thinking.

I would not want to do the short exposure technique with a 183, that would be an horrendous amount of data! Also i suspect that the read noise is a little too high and the dynamic range too low at very high gain, the 178 has less pixels and lower read noise via the 14bit A/D, 183 is only 12 bit.

Adam

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2 hours ago, ollypenrice said:

Indeed, the 'lucky imaging' fast frame approach to DS imaging is also in the air and may well be a game changer. The image in the link looks only at the bright core so it doesn't tell us anything about the potential for capturing faint signal but I still think that change may not be far away.

Olly

You just mix in a layer with longer subs for the fain stuff and bin for RGB, best of both worlds.

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The montage presentation is really quite stunning.

 

Although there is no loss of detail when viewed at full resolution,  I actually prefer it all on the screen where I can see the entire composition.

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18 hours ago, ollypenrice said:

I agree, but my argument as mentioned by Goran and published in Astronomy Now magazine in September 2018, didn't just make the case for a wider field of view from the refractor's reduced focal length. I also discussed the fact that I had been unable to extract more genuine galaxy detail from a 14 inch optimized Dall Kirkham than from our TEC140. The longer focal length certainly produced a larger screen 'object image' (and so a narrower FOV on the same sized chip) but what I found in the larger images was 'empty resolution.' That's to say that there was no significant difference in perceptible object detail. Because the data was taken on different nights the test was not entirely rigorous but I think it was valid on a 'real world' basis. 

The imager using the 6 inch (ish) refractor is going to have to make a good job of the small targets because a satisfying presentation will need to be at full size. There will be no hiding behind a 50% presentation!

Goran, I think you have vindicated the '6 inch refractor with small pixel camera' argument pretty clearly here. To be honest I expected the article to generate at least a bit of hostility but this hasn't been so and I've just been approached by a Dutch publication who'd like to translate some of it with Astronomy Now's permission (which has been granted.)  I believe that big refractors and small pixels are on the move! The fact that FLO are offering the Skywatcher Esprit 150 at £3999 (about what I paid for my second hand TEC140 six years ago...) makes it a competitively priced galaxy imaging scope as well as an easy and effective one.

Keep 'em coming!

Olly

Thanks Olly!

I am sure this large refractor could do even better if I had gone for longer exposures rather than more objects during the few clear nights I had. The total exposure time for each image varies between 3 and 7 hours, so emarrasing short. Also seeing has not been the best lately and therefore my guiding has suffered (RMS 0.8 -1.0"/pix). So there is more potential in this scope.

Since the pre-brexit price is only 3999 pounds maybe now is the time to log into the FLO site and order one.

 

 

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17 hours ago, wimvb said:

Now we just have to wait for images taken with a SW 150ED and a small pixel camera. That scope is half the price of its Esprit counterpart.

Very nice presentation Göran. The weather hasn't been in your favour this season. :icon_salut: :icon_salut:

Hopefully you get more opportunities after next full moon. Astro season will soon be at an end up here.

Thanks Wim! As you say the weather could have been better and the exposure times longer.

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11 hours ago, don4l said:

The montage presentation is really quite stunning.

 

Although there is no loss of detail when viewed at full resolution,  I actually prefer it all on the screen where I can see the entire composition.

Thanks Don!

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14 hours ago, tomato said:

I’m currently experimenting with an ASI 120 MM on the Esprit 150, with a view to acquiring an ASI 178 or 183 for galaxy imaging as opposed to the Atik 460 or similar. As usual, some clear, moonless darkness would be nice.

Olly, It’s by no means a scientific survey but I noted with interest that truss tube RCs were very thin on the ground at the Practical Astronomy show last weekend, while larger refractors were in abundance. This was in stark contrast to 4 years ago when RCs were on prominent display at the IAS. I am also sensing a shift in the established thinking.

True. Many suppliers poured time and effort into getting a better structure commissioned for the GSO RC mirror sets, for instance. Some of these projects, perhaps most, have been abandoned.

Olly

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