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TofuBoy

Gear for Astrophotography

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So after deciding to get the skywatcher explorer 150P, I would like to see what the best mount I can get.

The first option of getting the EQ3-2 with GOTO but the only concern is that some people have posted that having a DSLR with the scope might be a problem.

My second choice would be with getting a EQ5 Deluxe instead but with it being a bit pricer, would just getting it with the duel axis motors with no GOTO be ok.

Also how do those optional motors work if I add it on to the EQ5, I assume they can still track things as long as I point it at the thing I want it to follow first?

Edited by TofuBoy

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For AP and a 150P you are probably looking at the HEQ5, the EQ5 is good but not sure about it handling the weight of the 150P and the DSLR and whatever other bits, small but essential bits.

The set up of an equitorial is not point at whatever you want to see. Slight matter of accurate polar alignment. Not approximate but accurate. Throw in a polar scope as well, it the mount doesn't come with one.

You will need dual motors at least.

Add up the weight of the scope and DSLR and add on 20%, then see if that is about half the capability of the EQ5.

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For AP and a 150P you are probably looking at the HEQ5, the EQ5 is good but not sure about it handling the weight of the 150P and the DSLR and whatever other bits, small but essential bits.

The set up of an equitorial is not point at whatever you want to see. Slight matter of accurate polar alignment. Not approximate but accurate. Throw in a polar scope as well, it the mount doesn't come with one.

You will need dual motors at least.

Add up the weight of the scope and DSLR and add on 20%, then see if that is about half the capability of the EQ5.

thanks for the info, I would like to know though, how the motors work with once fitted. Do they know how to track on their own or would I need to input data in or what?

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The general opinion is HEQ5 is the most basic astrophotography mount. If you get a EQ5, you will be restricted to short exposure at short focal lengths or planetary imaging. Vibrations, mechanical errors and flex will become an issue on longer exposure.

The RA motors in the dual axis drive will track the sky, good enough for visual use but not for long exposure. If you choose to do long exposure, you need to provide continuous correction (guiding) to keep the mount on track. The motors on most mounts aren't accurate enough for long unguided exposure. Guiding can be done manually or using an autoguider.

If you use an autoguider, you will need a ST4 guide port on your mount controller. The standard Skywatcher dual axis drive does not have this port, you need the SW Synscan GOTO upgrade or a Vixen D3M dual axis drive for one.

Anyway these still wouldn't solve the problems associated with mount flexure and vibrations, so if you want to image DSO with a 150p you will need a HEQ5.

You should also get this book. Making Every Photon Count - Steve Richards It's written by one of the forum mod and highly recommended for beginner astrophotography.

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The general opinion is HEQ5 is the most basic astrophotography mount. If you get a EQ5, you will be restricted to short exposure at short focal lengths or planetary imaging. Vibrations, mechanical errors and flex will become an issue on longer exposure.

The RA motors in the dual axis drive will track the sky, good enough for visual use but not for long exposure. If you choose to do long exposure, you need to provide continuous correction (guiding) to keep the mount on track. The motors on most mounts aren't accurate enough for long unguided exposure. Guiding can be done manually or using an autoguider.

If you use an autoguider, you will need a ST4 guide port on your mount controller. The standard Skywatcher dual axis drive does not have this port, you need the SW Synscan GOTO upgrade or a Vixen D3M dual axis drive for one.

Anyway these still wouldn't solve the problems associated with mount flexure and vibrations, so if you want to image DSO with a 150p you will need a HEQ5.

You should also get this book. Making Every Photon Count - Steve Richards It's written by one of the forum mod and highly recommended for beginner astrophotography.

thanks for your input, will be getting that book first then before I start getting my scope and mount. One thing that I would also like to ask though

everyone has been saying that imaging with longer exposures may be a problem with vibrations etc from having a 'lighter' mount but what I want to know is how long these exposures are? instead of doing very long exposures for DSO, could you not just instead do many many shorter exposures or would that not be viable.

My only concern is that getting the HEQ5 may be slightly out of my price range if I decide to get motors and auto guiders etc

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could you not just instead do many many shorter exposures or would that not be viable.

Not really, here's why....

Combining images allows for the subtraction of noise, this increases the signal to noise ratio and can help bring out more details. Note I said "bring out more details" not capture more details.

Here's the rub, when capturing faint objects you are dealing with a few photons hitting the sensors very infrequently. You have to have so many photons hit a sensor to make an impression. If your shutter is open for 10 seconds at a time and the required number of photons accumulate every 30 seconds then none of your frames will have that pixel illuminated.

The same holds true for cranking up the ISO, if there are not enough photons hitting the sensor, cranking the ISO from 100-3200 makes no difference as all that really does is amplify the signal. Basic math says that one million times zero is still zero, so you have to have a signal to start with.

Now there are plenty of targets that you do get plenty of light with 10 second exposures such as M42 and M31 so that you can do something with them. Then there are plenty of targets that will probably not work at all for.

Allan

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I've found that it takes me a long time to save up for things, being a pensioner, but eventually I am getting what I want :) You need a lot of patience in this game! I think even with a good income you'd still need a lot of patience - it takes a lot of practice to get good results.

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When I shoot unguided on an EQ5 with a 4kg 80mm F480mm Apo and a 6MP DSLR, less than 50% of the 3 minutes subs are usable. None at 5 minutes.

A 150p has a longer focal length, heavier tube, worse load distribution, more susceptible to wind. Your DSLR may have a 10+MP sensor, which means smaller pixel size and will require greater tracking accuracy. In other word, you will need very short exposure to get an acceptable image.

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So getting the setup I want will mean that I won't be able to do long exposures unless I go all in with a HEQ5. That wouldn't be too bad as long as there are at least some targets for me to image. I never expected to be able to image everything in the sky of course haha but as long as there is still plenty for me to do with shorter exposures I'd be happy.

Being young and eager has its down sides :)

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There is still plenty to do with short exposures, it just depends on what you want to do vs what you can.

When I got into AP I knew what I wanted, to be able to get some nebulas such as NGC6992 and NGC6960, which I can not imagine getting with short exposures (my 6960 shots required ISO 1600 for 360 seconds) so for me, it would not have worked at all.

On the flip side, I have seen some amazing stuff in widefield and with some brighter targets such as M42/M43 and M31 with short exposures, but that isn't what I wanted.

So again, it just depends.

Allan

Edited by Flea77

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A reasonable alternative is the Celestron CG5GT Goto. You can get them second hand around £250-£350 depending on age and condition. It has 2" dia steel legs so a little more solid, heavier, and stable than the EQ5. It also has uprated worm drives and gearing and the database is much bigger and the software more sophisticated.

It will handle the 150P with ease - I've had 9min subs guided when I had one. The only downside is that it's a tad noisy when slewing in both axes (but silent tracking).

Hope that helps :)

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With the EQ3 Pro or EQ3-2 + dual drives you should be able to get 60-90 sec exposures. Stack enough of those and you can get some quite nice images of the brighter objects. It is possible (most of my images were taken with that combo) but it was hard work and you will be able to do much better with a sturdier mount.

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very interesting stuff. might have to hold out a bit longer and save up that extra few £££. lastly though, I know that the longest exposure I can get on my 600D is 30secs I think and then there is bulb so I take it you would have to connected it to my laptop to get longer 360sec expo etc

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hey rik, was looking though your images, just wondering about the one with you sitting in the garden. what is that on the end of your scope. looks like brown paper tube?

Edited by TofuBoy

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You could use a timer remote. they can be picked up for less than £20, but there are lots of reasons why using a lap top to control your camera is better.

I use Astrophotography Tool to run my 1000D. It's great.

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hey rik, was looking though your images, just wondering about the one with you sitting in the garden. what is that on the end of your scope. looks like brown paper tube?

It's a rolled up Asda black foam camping mat. Looks loopy but it keeps the dew off the secondary :)

Edited by RikM

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After a bit more time looking around, how does the Celestron CG-5 compare to the EQ5 and HEQ5 Pro.

I have read that it is sturdier then the EQ5 so in that sense I will assume that it may be better if I use it for AP but what about comparing it to the more expensive HEQ5 Pro

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Hey,

I have a 150p with EQ3-2 mount and Duel Motors, i agree that for getting into imaging (which is what i want to do) a more solid mount is better but for me at the moment i think the EQ3-2 is fine, gives me time to learn things.

I manage to get 60-90sec exposures with my dslr and maybe more if i was not in a light polluted area and with little or no wind.

I got my scope about a month ago and plan to stick with it, i will upgrade the mount in a year or so to an EQ5 or HEQ5, at the moment im still learning how to process images and what is in the sky.

Here is an example of what you could do with my set up:

Andromeda Galaxy (M31) | Flickr - Photo Sharing!

This was my first image taken with about 20 odd 30-60 sec subs and stacked in Deep Sky Stacker. Was taken in my back garden which is heavily light polluted so i don't think its too bad. Still a lot of room for improvement.

Hope this helps

Matt

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I would strongly suggest... if you possibly can, to wait until a HEQ5 comes up second hand and grab one of those... in fact, there's one on the for sale section at the mo for just over £500, about what I paid for mine. They don't really loose value so you can always sell it on again if at some stage you change your mind about the hobby.

With the HEQ5 you have everything you need, neatly pre-assembled and ready to go and it is VERY capable of doing everything you will want of it in your first year or two of astrophotography.

With 30 - 90 second exposures there is an awful lot you can capture... a lot of galaxies, most globulars, and a lot of the brighter nebulae. You'll find your expectations rise rapidly after you've captured your first few images... and eventually only LOOOONG guided exposures will give you the quality of images you are after... I reached that point after about 6 months :-)

Guiding is great once you get there but I've certainly had brilliant fun capturing my first unguided astro images this year with a DSLR a few different scopes (I seem to work through changing scopes every two months at the mo :-) and a HEQ5.

I really can't recomend the HEQ5 enough... it'll really do everything you want and more... and until the payload weight starts pushing 15kg or so, you won't need anything more.

Ben

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Many thanks for the advice! can't get onto that buy/sell forum yet so I well look around for a second hand one elsewhere. That or wait a bit longer and save up haha. Probably go for the SynTrek non GOTO one if I can find it though cause I can connect my computer up to it.

Edited by TofuBoy

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The black one is the basic model. Fine for visual use but the Pro Synscan version has uprated more accurate motors and an autoguider port so you can guide it. That is the one you want for astrophotography. I am not sure if you still get hold of the midrange Syntrek one. Which is basically the Pro without the handset.

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