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Recommend shots 50mm no tracking :)

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#1 gerryberry

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Posted 10 April 2021 - 08:00 AM

So I’ve been out a few times thanks for everyone’s help, practicing a lot with stacking processing and capturing so happy with progress so far
Telescope with tracking mount due in mid May so in the meantime what’s the best think I can capture with a standard tripod and 50mm lens do people think?

I have seen some people capture nice nebula etc with this kit, I have a good view of the IRis nebula tonight but with a 50mm and 1.8 am I asking for too much?

#2 sg6

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Posted 10 April 2021 - 09:10 AM

Iris is about 1/3 of a degree and at a 50mm lens that give an image of 0.3mm - seems a bit small. Problem is the 50mm bit, everything will be small. Even M31 would just make 2.6mm. Although M31 is the obvious. M33 would be around 1mm image at the sensor. Same for M42.

 

How about M45 ?

2 degrees so just under 2mm (still small) however it is often described as slightly larger say 2.5 degrees. Reasonably bright, you may get nebulosity - just do't count on it.

 

That sort of brings in the Hyades cluster, that is more spread out - they have had longer to drift apart - but is around 3+ degrees, and you will get the big red Aldebaren in.

 

Globular clusters are small so will discard them.

 

The big nebula like The Veil are dim, very dim. So too many exposures and time.

 

Double Cluster maybe.

How about centering Alnilam (center star of Orions belt). Belt is around 3+ degrees, and sits central against the cluster Collinder 70.

 

So the bigish obvious to me are: M45, Hyades then the Belt stars and CR70.

The belt stars are the more unimaged, try them.

 

I would also attempt to mark where one of the belt stars sit on the rear view and recenter it say every 5 exposures.

 

Iris looks interesting but will be small, very small and with a50mm you would I think need to target something of some size.

 

I assume you are using a DSLR?


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#3 fewayne

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Posted 10 April 2021 - 09:15 AM

Well, the nebula is all of 10' angular diameter, so it's  going to be just a speck in  the image. On my DSLR it would be 30 pixels.

 

You may have already heard about this, but  a previsualization program  like  Stellarium  or  KStars is a  great help. You can also use telescopius.com. You can enter your own sensor size from your camera's specs, and the focal length you're using. I  did a couple of screen shots from Stellarium but CN is being cranky and they won't upload.

 

If Orion is still high enough in the sky, a  50 does pretty well at M42, the Flame  Nebula, and Barnard's Loop if you  shoot enough sub-exposures. I did this  with Pentax's AstroTracer so I was able to do reasonably long exposures  without  trailing,  but  it's possible without.


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#4 bobzeq25

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Posted 10 April 2021 - 09:30 AM

So I’ve been out a few times thanks for everyone’s help, practicing a lot with stacking processing and capturing so happy with progress so far
Telescope with tracking mount due in mid May so in the meantime what’s the best think I can capture with a standard tripod and 50mm lens do people think?

I have seen some people capture nice nebula etc with this kit, I have a good view of the IRis nebula tonight but with a 50mm and 1.8 am I asking for too much?

50mm is fine.  You just have to have reasonable expectations.  They should not include targets like the Iris nebula. 

 

Shoot constellations.  The best might be the Big Dipper right now.  Leo is another possibility.  The Milky Way is another possibility, not well positioned now.

 

Do it right.  Many subs, I'd say 100 would be a decent start.   Bias, flats, darks.  Learn the techniques, learn to process data.

 

The arrival of summer will bring Cygnus into position, one of the best targets for 50mm.  Here's one of mine.  50mm, tripod, 100 X 7seconds.  The camera had been modified for increased sensitivity to emission nebulae.

 

Bottom line.  Don't expect to do the same targets people with telescopes do.  You said you saw some images with 50mm you liked, look at the targets people imaged.

 

Cygnus_small.jpg


Edited by bobzeq25, 10 April 2021 - 09:33 AM.

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#5 Reece

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Posted 10 April 2021 - 09:30 AM

This is website is very helpful: Telescopius.com

Go to "Targets" -> "Deep Sky" and sort results by "Surface Brightness". 

Go to the "Filter" option and for "Apparent Size" put "From 1 Degree" on the left line, leaving the right line blank.

 

This will sort all deep space objects available at your location by their surface brightness so long as they are at least 1 degree in size. Anything smaller than 1 degree will be very small at 50mm.

 

It is very important to sort the results by "Surface Brightness" and not just pick which objects seem most interesting because without a tracker some of these objects will taken many, many hours to get a picture of if it is even possible. 

 

Suitable targets where I live include the North American Nebula, Elephant Trunk, California Nebula. You could look at Astrobin and see what other people have been taking photos of with your lens. They might have more ideas for you of what is possible. I'm not sure if you have one, however the 18-55mm lenses that are bundled with a lot of cameras make a pretty decent budget astrophotography lens at 18mm. Because you don't have your tracker yet, you can get a lot more exposure time at smaller focal lengths. At 18mm you would not be getting pictures of Deep Space Objects, however you could capture the Milky Way and constellations. Have fun and Good Luck! 


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#6 gerryberry

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Posted 10 April 2021 - 12:17 PM

This is website is very helpful: Telescopius.com

Go to "Targets" -> "Deep Sky" and sort results by "Surface Brightness". 

Go to the "Filter" option and for "Apparent Size" put "From 1 Degree" on the left line, leaving the right line blank.

 

This will sort all deep space objects available at your location by their surface brightness so long as they are at least 1 degree in size. Anything smaller than 1 degree will be very small at 50mm.

 

It is very important to sort the results by "Surface Brightness" and not just pick which objects seem most interesting because without a tracker some of these objects will taken many, many hours to get a picture of if it is even possible. 

 

Suitable targets where I live include the North American Nebula, Elephant Trunk, California Nebula. You could look at Astrobin and see what other people have been taking photos of with your lens. They might have more ideas for you of what is possible. I'm not sure if you have one, however the 18-55mm lenses that are bundled with a lot of cameras make a pretty decent budget astrophotography lens at 18mm. Because you don't have your tracker yet, you can get a lot more exposure time at smaller focal lengths. At 18mm you would not be getting pictures of Deep Space Objects, however you could capture the Milky Way and constellations. Have fun and Good Luck! 

thanks for everyones input - based on feedback elephant trunk looks good to capture on stellarium from my position

 

I was thinking 50mm, 1.8 and ISO maybe 3200 with 6 second exposures - ISO too high would people think? Ive taken a few constellation photos but do want to try and get some more "colours"



#7 Reece

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Posted 10 April 2021 - 12:24 PM

You are most welcome. What is the brand + model of camera that you have? Some older cameras like my Canon 40D have an ISO 3200 setting however it is not a setting you would ever want to use.



#8 gerryberry

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Posted 10 April 2021 - 12:25 PM

You are most welcome. What is the brand + model of camera that you have? Some older cameras like my Canon 40D have an ISO 3200 setting however it is not a setting you would ever want to use.

canon eos 2000d with the "nifty 50" lens



#9 Reece

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Posted 10 April 2021 - 12:41 PM

This website is very helpful: PhotonstoPhotos.net

 

According to their read noise data, you would want to use at least ISO 800. Are you planning to edit your photos in an image editing program after you have taken them? If you are comfortable doing that, you might get a better result using ISO 800/1600 instead of 3200.

 

 

canon eos 2000d with the "nifty 50" lens

 


Edited by Reece, 10 April 2021 - 12:41 PM.


#10 gerryberry

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Posted 10 April 2021 - 12:48 PM

yes ive been practicing with siril and gimp - below is my most recent image at 1600 ISO - very junior when it comes to image editing but let me know if its "ok" enough and I will go with 1600 then for the elephant trunk

 

https://imgur.com/a/NFYu4r2

 

 

above image was taken with the same setting im planning on using - 50mm, 1.8, 6 seconds and ISO 1600 - I did about 90 X 6 second shots and refocussed and reframed after 30 shots of each


Edited by gerryberry, 10 April 2021 - 12:49 PM.

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#11 Reece

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Posted 10 April 2021 - 12:53 PM

Great job! That sounds like a very good plan. All the Best! 



#12 Hesiod

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Posted 10 April 2021 - 01:05 PM

Closer to the pole you aim the camera, longer the window before trailing appears.

That is useful if are no willing to take too many shots, which can be really nasty for several reasons.

Of course you are free to accept a certain degree of elongation of your stars (which may be addressed to a certain extent in PP): it may be well worth in order to avoid too high ISOs or being forced to stretch too much the stack.

The "Elephant trunk" is actually pretty small and, being embedded in a mostly deep red nebula, not the easiest pick for an unmodded DSLR (a fair share of the red signal is clipped by the sensor's filters, so would need a much longer integration to "see" it well compared to what is possible with dedicated astrocameras or astro-modded DSLR); however, if are shooting from a truly dark site, Cepheus is a wonderful target at 50mm even if I would prefer a different season.

If are in the dark, another great target is Polaris: the star is surrounded by faint, grey-sh and huge nebulae, which are actually made from dust outside our galaxy and reflecting the Milky Way's own integrated light.

 

Another option could be to take a picture of a constellation and underline the main stars either in PP (a gentle selective blur) or a "flou" filter placed directly on the objective.

Here an example I took (the "filter" was kindly provided by the sky itself through a thin layer of clouds): the picture was taken with a tracking device, but this is not a necessity

gallery_215679_7885_717915.jpg


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