Tamron SP 150-600 F/5-6.3 Is it good for AP

[Brian W (Brian)]

It will be a while before I have the funds but is the Tamron SP 150-600mm f/5-6.3 Di USD Lens for Sony good for nebulae, star clusters and globular clusters? Perhaps even the moon?
Brian

[blink138 (Pat)]

it might be a tad slow for astro brian?
plus those sorts of zooms do not have the best optics for our game i don't think
perhaps others could chip in here too
pat

[Brian W (Brian)]

Originally Posted by blink138

it might be a tad slow for astro brian?
plus those sorts of zooms do not have the best optics for our game i don't think
perhaps others could chip in here too
pat

I hope others will too. What would you recommend as a good lens for a Sony A mount for deep space.Tamron also makes a 180 macro. Would it do for deep space. It certainly is sharp but I'm unsure of the magnification for globular clusters or something like M42

[that_guy (Tony)]

for that price, couldnt you afford a small apo or ED refractor with comparable focal lenghts? Surely they'll have better optics than a zoom lens.

[Brian W (Brian)]

Originally Posted by that_guy

for that price, couldnt you afford a small apo or ED refractor with comparable focal lenghts? Surely they'll have better optics than a zoom lens.

I should very much like to stay with DSLR astrophotography. I'm not at all sure that a comparably priced apo / ed would have better optics than the Tamron 180. Though I'm open to being shown the error of my beliefs

[kens (Ken)]

You can make it work but the challenges include:
How to get a solid setup without flexure
How to get fine focus and lock it in
How to lock the focal length - a fixed focal length is normally preferred
Tracking and guiding: essential for DSOs at 600m focal length
Internal reflections: Good OTAs are either flocked or baffled. Tamron's nano-coating may address this satisfactorily.

For tracking and guiding at 600mm you'll want a suitable mount. In AP the mount is the primary consideration.

[h0ughy (David)]

single answer - no

yes you can take a photo and get a result but you wont be happy with it. be good for a lunar or solar shot with an appropriate filter on the front, but for deep sky no.

I have a tamron 150-600

for the money your looking at get an ed80, either way you will need a heqpro5 minimum

[Brian W (Brian)]

Originally Posted by h0ughy

single answer - no

yes you can take a photo and get a result but you wont be happy with it. be good for a lunar or solar shot with an appropriate filter on the front, but for deep sky no.

I have a tamron 150-600

for the money your looking at get an ed80, either way you will need a heqpro5 minimum

What's your opinion of a Bresser Exos-2? I know it is a manual tracking mount but with my skies I'm lucky to get an hour of clear.

I really would like to stay with straight DSLR. But the ed80 is less expensive.

[Brian W (Brian)]

Originally Posted by kens

You can make it work but the challenges include:
How to get a solid setup without flexure
How to get fine focus and lock it in
How to lock the focal length - a fixed focal length is normally preferred
Tracking and guiding: essential for DSOs at 600m focal length
Internal reflections: Good OTAs are either flocked or baffled. Tamron's nano-coating may address this satisfactorily.

For tracking and guiding at 600mm you'll want a suitable mount. In AP the mount is the primary consideration.

If I go pure DSLR:
either a pier or a Bresser Exos-2. if a pier then a camera carrier
manually focus and with a good lens there is no barrel slip. the focus stays where it is set
probably manual tracking
Brian

[h0ughy (David)]

Originally Posted by Brian W

What's your opinion of a Bresser Exos-2? I know it is a manual tracking mount but with my skies I'm lucky to get an hour of clear.

I really would like to stay with straight DSLR. But the ed80 is less expensive.

if that's all you will get then its pointless doing deep sky photography. you would be better off using a 50mm lens or 135mm using a tracking mount like https://www.bintel.com.au/product/sk...-bundle-black/ or something of that ilk . setup get a few happy snaps. to do any real justice you will need a few hours on each target. if your going visual then get a 8-12" dob for visual. sorry but you cant mix a cheap nasty mount and expect to get great images. you need tracking both axis and autoguiding. to be honest the bare minimum is a heqpro5

as for your mount choice - i reserve the right not to answer on the grounds that i may not say what you want to hear

[Brian W (Brian)]

Originally Posted by h0ughy

if that's all you will get then its pointless doing deep sky photography. you would be better off using a 50mm lens or 135mm using a tracking mount like https://www.bintel.com.au/product/sk...-bundle-black/ or something of that ilk . setup get a few happy snaps. to do any real justice you will need a few hours on each target. if your going visual then get a 8-12" dob for visual. sorry but you cant mix a cheap nasty mount and expect to get great images. you need tracking both axis and autoguiding. to be honest the bare minimum is a heqpro5

as for your mount choice - i reserve the right not to answer on the grounds that i may not say what you want to hear

fair enough. The Star Adventurer is a good tracking system.

[Brian W (Brian)]

Originally Posted by h0ughy

if that's all you will get then its pointless doing deep sky photography. you would be better off using a 50mm lens or 135mm using a tracking mount like https://www.bintel.com.au/product/sk...-bundle-black/ or something of that ilk . setup get a few happy snaps. to do any real justice you will need a few hours on each target. if your going visual then get a 8-12" dob for visual. sorry but you cant mix a cheap nasty mount and expect to get great images. you need tracking both axis and autoguiding. to be honest the bare minimum is a heqpro5

as for your mount choice - i reserve the right not to answer on the grounds that i may not say what you want to hear

Let me try this from a different perspective. Then if I still make no sense my apologies for wasting band width.

Right now I am using my Sony Alpha a58 connected to a stable Slik tripod on one end and a Tamron 90mm 272E on the other. To cut down on vibration I use wireless shutter release.

On a good night I can produce a shot that is close to what I used to see through my 4.5" Orion short tube reflector. With the added bonus of colour.

I would like to move up to what I could see through my 8" Lightbridge.

Can I do this with a new motorized tracking 8" Dob? With a manual 8" dob?

Can I do it using the Skywatcher Adventurer (or some other camera tracker) with an appropriate lens attached to my camera.

If I'm just wasting bandwidth you have my heartfelt apologies.
Brian

[kens (Ken)]

Theres a huge difference between taking shots with a 90mm f/2.8 and a 600mm at f/6.3.
The A58 has pixels 4.3um across. With a 90mm lens that gives a pixel scale of around 10 arc seconds per pixel. At 600m the pixel scale becomes around 1.5 arc seconds per pixel.
The motion of the stars due to earths rotation is 15 arc seconds per second. So at 90mm you get a star trail of 1.5 pixels with a 1 second expsoure. At 600mm that becomes a 10 pixel star trail. But with extended objects the f/ ratio difference means (simplisticaly) you need nearly 5 times the exposure. So now your trails on the 600mm are 50 pixels long.
So you obviously need a tracking mount.
The next issue you face is periodic error - variations in the tracking rate due to mechanical limitations in the mount. A mount such as the HEQ5 (which David quite rightly pointed out is regarded as a bare minimum for good astrophotography) has a periodic error in the order of 30 arcseconds over a 10 minute period. So every 5 minutes it moves 30 arc seconds one way then in the next 5 minutes it moves 30 arc seconds the next way. That's 20 pixels at 600mm FL over a 5 minute exposure. That's the order of exposure time you would expect for faint objects like galaxies and nebulae.
The mount you linked to would typically have considerably more periodic error than the HEQ5 as would the star adventurer.
The way to counteract periodic error is autoguiding. For that you use a second scope and camera pointed at a guide star that takes exposures every few seconds. Guiding software identifies small movements of the star and sends corrective movements to a suitably functional mount. These movements are typically fractions of an arc second.
So now you need a mount that can take not only the imaging scope/lens and camera but also a guide scope and camera.
To get an idea of how much an arc second is when considering vibration, flexure etc. A movement of around 5 microns at 1 metre distance is about 1 arc second.

So now lets consider the Dob. It cannot track the stars accurately because it does not rotate about the polar axis. Even if you had the motors and electronic smarts to track the stars you would get field rotation. That means star trails that form arcs around the central target because, relative to the stars, the camera is rotating as the scope tracks across the sky. An equatorial mount does not have this problem (simplistically - theres then the issue of Polar Alignment error).

In astrophotography the mount is the most important piece of equipment.

[Brian W (Brian)]

Originally Posted by kens

Theres a huge difference between taking shots with a 90mm f/2.8 and a 600mm at f/6.3.
The A58 has pixels 4.3um across. With a 90mm lens that gives a pixel scale of around 10 arc seconds per pixel. At 600m the pixel scale becomes around 1.5 arc seconds per pixel.
The motion of the stars due to earths rotation is 15 arc seconds per second. So at 90mm you get a star trail of 1.5 pixels with a 1 second expsoure. At 600mm that becomes a 10 pixel star trail. But with extended objects the f/ ratio difference means (simplisticaly) you need nearly 5 times the exposure. So now your trails on the 600mm are 50 pixels long.
So you obviously need a tracking mount.
The next issue you face is periodic error - variations in the tracking rate due to mechanical limitations in the mount. A mount such as the HEQ5 (which David quite rightly pointed out is regarded as a bare minimum for good astrophotography) has a periodic error in the order of 30 arcseconds over a 10 minute period. So every 5 minutes it moves 30 arc seconds one way then in the next 5 minutes it moves 30 arc seconds the next way. That's 20 pixels at 600mm FL over a 5 minute exposure. That's the order of exposure time you would expect for faint objects like galaxies and nebulae.
The mount you linked to would typically have considerably more periodic error than the HEQ5 as would the star adventurer.
The way to counteract periodic error is autoguiding. For that you use a second scope and camera pointed at a guide star that takes exposures every few seconds. Guiding software identifies small movements of the star and sends corrective movements to a suitably functional mount. These movements are typically fractions of an arc second.
So now you need a mount that can take not only the imaging scope/lens and camera but also a guide scope and camera.
To get an idea of how much an arc second is when considering vibration, flexure etc. A movement of around 5 microns at 1 metre distance is about 1 arc second.

So now lets consider the Dob. It cannot track the stars accurately because it does not rotate about the polar axis. Even if you had the motors and electronic smarts to track the stars you would get field rotation. That means star trails that form arcs around the central target because, relative to the stars, the camera is rotating as the scope tracks across the sky. An equatorial mount does not have this problem (simplistically - theres then the issue of Polar Alignment error).

In astrophotography the mount is the most important piece of equipment.

What you say is undoubtedly true. And as I can't afford even the bare minimum I offer my apologies for wasting your time.
Brian

[Atmos (Colin)]

Everything that has been said here so far is correct BUT there are other ways to go about it.
The ultimate question is, what is your budget?

You are far better off getting an equatorial mount and using your current camera/lens combo. Doing this is the single biggest change that you can make. Taking 0.5s exposures with a 600mm lens is just not going to be what you're looking for. Yes, it'll allow you to zoom in on those star clusters but you'll never get a result you're really happy with.

Both of the images below were taken with unguided with what would be considered as a heavy duty Sky Watcher Star Adventurer.

http://www.astrobin.com/301645/
http://www.astrobin.com/301679/

The below shot was taken with a much better mount but I've had similar results with the HEQ5 that was used in the shots above.

http://www.astrobin.com/304742/

I do almost all of my wide field photography with an 8 year old mount with servo motors that hasn't been produced since around the time I bought it. It has a much higher weight capacity than the Star Adventurer BUT the Star Adventurer will for the most part do just as well with a DSLR and lens setup.

I'd suggest using the Star Adventurer with your 90mm and get your head around using that setup. When you want to upgrade your lens you can either get something along the lines of an ED80 or a 65mm ED Quadruplet F/6.5 (there are a few iterations of this) but your first step should be for an equatorial tracking mount.

[Brian W (Brian)]

Originally Posted by Atmos

Everything that has been said here so far is correct BUT there are other ways to go about it.
The ultimate question is, what is your budget?

You are far better off getting an equatorial mount and using your current camera/lens combo. Doing this is the single biggest change that you can make. Taking 0.5s exposures with a 600mm lens is just not going to be what you're looking for. Yes, it'll allow you to zoom in on those star clusters but you'll never get a result you're really happy with.

Both of the images below were taken with unguided with what would be considered as a heavy duty Sky Watcher Star Adventurer.

http://www.astrobin.com/301645/
http://www.astrobin.com/301679/

The below shot was taken with a much better mount but I've had similar results with the HEQ5 that was used in the shots above.

http://www.astrobin.com/304742/

I do almost all of my wide field photography with an 8 year old mount with servo motors that hasn't been produced since around the time I bought it. It has a much higher weight capacity than the Star Adventurer BUT the Star Adventurer will for the most part do just as well with a DSLR and lens setup.

I'd suggest using the Star Adventurer with your 90mm and get your head around using that setup. When you want to upgrade your lens you can either get something along the lines of an ED80 or a 65mm ED Quadruplet F/6.5 (there are a few iterations of this) but your first step should be for an equatorial tracking mount.

so the Star Adventurer on a pier might be a good way to go?

[Atmos (Colin)]

Pier or a steady tripod. A half decent tripod would had a bit to the cost.

https://www.astrobin.com/gear/25666/...ar-adventurer/

This is what people have achieved with the Star Adeventurer.

[Brian W (Brian)]

Originally Posted by Atmos

Pier or a steady tripod. A half decent tripod would had a bit to the cost.

https://www.astrobin.com/gear/25666/...ar-adventurer/

This is what people have achieved with the Star Adeventurer.

Strip out 6he colour and that's close to what I saw in an 8" dob. Not quite so defined but it was not averted vision time.

And just to be perfectly clear I am NOT expecting to get shots like these for quite a while if ever. It's just nice to believe in the dream.

[Regulus (Trevor)]

I've wondered about this lens too.
Actually it is pretty fast at 6.3. The ED 80 is 7.5, and this is a flat-field lens too.
I'm not sure how I would mount it to get it truly stable though. I don't think the mounting foot would be ideal, even though it is used on tripods, but that would be at a higher shutter speed that would thwart vibrations. There's an obvious spot at the rear for a mounting ring where the supplied 'foot' attaches. But toward the fron, only the spot between the zoom and focus rings, which would need a thin ring to avoid the mode buttons there. But doable with some thought put into it.
Optical construction is ok: "...three LD (Low Dispersion) lens elements which completely eliminate axial and transverse chromatic aberrations. It also features upgraded optical construction (21 elements in 13 groups). Anti-reflection technologies, eBAND (Extended Bandwidth & Angular-Dependency) Coating and BBAR (Broad-Band Anti-Reflection) Coating improve light transmission and suppress internal reflections, including light reflected off the camera’s image sensors."

I have also wondered about the 500/600mm Samyang mirror lenses, but they may not have the resolution you'd get from a good scope.

Trev

[omegacrux (David)]

I highly recommend a Star Adventure , easy to use and set up , mine is on a survey tripod , cheap as chips & solid , using mine at 80mm f4 picks up galaxies , happy as with it

David