New toy...this could become an expensive hobby!

[jimi43]

haha, so is that mirror out of the black scope you showed? Or another?.....

As a person whose two favourite shops are bootfairs and FleaBay....and since the weather precludes the former...I picked it up on FleaBay for a score.

My intention was to build my own version of the "black" (dark blue) Newtonian which is from Orion Optics originally (secondhand from a guy in Essex)....but is of exactly the same diameter.

I wanted to understand optics a bit better...build things of my own...although I stopped short of grinding my own glass...I wanted to get out there and looking a the stars.

The cloudy nights since 1813 certainly have aided my tinkering and research but I'm getting rather fed up with looking upwards at dusk and seeing the never-ending clouds rolling in from Dover.

Now I have the F-number of the mirror....I know where the prime focus of this mirror should be hence where I need to put the secondary mirror and draw tube for the eyepiece...

I'm actually pondering the possibility of building a "Dobsonian" which is a more portable ingenious design of mounting a mirror....

CLICK

That beautiful design is by a guy called Sean Graham...made of hardwood...an ideal merging of my two loves!

Cheers

Jim

 

[mickthetree]

WOW! What a piece of kit!! What is the diameter of the mirror you showed? Looking at clouds is almost as frustrating as looking at the inside of the box it came in. Mid moving house and its all packed away.

I love that video. Alfie clearly just wants to "help".

 

[jimi43]

WOW! What a piece of kit!! What is the diameter of the mirror you showed? Looking at clouds is almost as frustrating as looking at the inside of the box it came in. Mid moving house and its all packed away.

I love that video. Alfie clearly just wants to "help".

It's 8 1/2 inches Mick.

Apparently...the great man himself suggested that this was about the ideal size...for a Newtonian. A combination of speed and portability...just on the limit really.

With the Dobsonian design...the portability issue becomes less of a problem as the whole thing folds up and can be rolled away for later.

The idea is that the whole optical tube assembly is rather like an astronomical "Weeble"....the centre of gravity and weight are very low down and the pivot point is the base...running on a set of bearings for azimuth and on Teflon semi-circles for elevation. Once you get used to using one...you can fair whiz around the skies...or so I'm told!

I would have preferred a larger mirror for this design but it's a healthy size....and with such provenance...a gem!

Jim

 

[verney]

I'm actually pondering the possibility of building a "Dobsonian" which is a more portable ingenious design of mounting a mirror....

CLICK

That is one beautiful dobsonian. I have one scope on order from here:
http://www.sumerianoptics.com/en/

 

[jimi43]

I'm actually pondering the possibility of building a "Dobsonian" which is a more portable ingenious design of mounting a mirror....

CLICK

That is one beautiful dobsonian. I have one scope on order from here:
http://www.sumerianoptics.com/en/

Yes...those Sumerian telescopes are very innovative...I will certainly be using some of the design ideas from companies like this when building my scope.

Tentative plans will include exotic woods at some point in the design...sprinkled with some carbon fibre parts...and anodized aluminium...I can see quite a harmony there as with infill planes...beautiful woods and steel working in concert.

Thanks for the comments.

Jim

 

[Paul.J]

Blimey Jim you certainly got a lot more data out of that M31 image :shock:
It was only a single 30 sec shot,shot originaly in RAW.
What programme do you use for your photo editing?
That looks like a big upgrade Jim,is that an NEQ6 mount?
Great find on the mirror.

 

[jimi43]

Blimey Jim you certainly got a lot more data out of that M31 image :shock:
It was only a single 30 sec shot,shot originaly in RAW.
What programme do you use for your photo editing?
That looks like a big upgrade Jim,is that an NEQ6 mount?
Great find on the mirror.

Hi Paul

I put it through CS3...just levels and curves. If you pm me the RAW if you still have it I can probably get some colour out of it. You need longer and more subs and probably guiding....but let's see what we can do.

Yes...it's the NEQ6 Pro..got it secondhand.

Cheers

Jim

 

[bugbear]

You need longer and more subs and probably guiding....

People were taking 1-2 hour exposures on film long before guiding!

BugBear

 

[jimi43]

You need longer and more subs and probably guiding....

People were taking 1-2 hour exposures on film long before guiding!

BugBear

People walked in the woods before scouting too..BB...but it just made it more fun and less likely to go astray! :mrgreen:

J

 

[bugbear]

You need longer and more subs and probably guiding....

People were taking 1-2 hour exposures on film long before guiding!

BugBear

People walked in the woods before scouting too..BB...but it just made it more fun and less likely to go astray! :mrgreen:

J

What I mean is, a well adjusted "clock drive" can works well, especially (in the modern era) if you're using stacking, so that each exposure is "only" 30 seconds.

http://www.flickr.com/photos/2lazy7/4282723098/

Guiding requires a fully motorised mount AND a second telescope AND a second camera (I'll take the laptop for granted).

BugBear

 

[jimi43]

QUOTE REMOVED TO ALLOW FOR REPLY LIMIT....

People were taking 1-2 hour exposures on film long before guiding!

BugBear

People walked in the woods before scouting too..BB...but it just made it more fun and less likely to go astray! :mrgreen:

J

What I mean is, a well adjusted "clock drive" can works well, especially (in the modern era) if you're using stacking, so that each exposure is "only" 30 seconds.

http://www.flickr.com/photos/2lazy7/4282723098/

Guiding requires a fully motorised mount AND a second telescope AND a second camera (I'll take the laptop for granted).

BugBear

Hi my friend.

Yes...I knew what you had in mind...but the temptation of an available pun was hard to resist...after all...the COAT has been used far too often for the real weather lately!

Apologies if I sounded sarcastic!

I thought...though I may be wrong...that taking lots of shorter images and appropriate darks led to a higher signal to noise ratio because of the way stacking programmes were able to cope with the data. The inclusion of flats to reduce dust mites and bias corrections are not strictly necessary either but help in the final image quality.

I actually meant to say "tracking" rather than guiding though...my fault. And I think that was what you meant too..by your reference to clocks. Autoguiding prevents cigar stars and longer trails for super long exposures where tracking errors start to take effect.

I'm getting "Making Every Photon Count" by Steve Richards....recommended by a friend. I'll come back to this when I've read it...I'm still very very low down on this steep learning curve.

With careful selection of the equipment you either don't have to have all the gear or you can use it for other things as well.

A cheap webcam on the finderscope will suffice and work in PHD...I know...I tried it with a ten quid Xbox camera from Amazon...

...which I promptly took apart...flashed the LEDs to stop them interfering...took out the IR filter and stuck a bit of tubing from an old vacuum cleaner on the front to act as a nose...it worked fine on my fake "LED torch cluster" in the dark kitchen....

...until passing COMET ALFIE and my son returning from a short elliptical orbit to the Poo Galaxy caused a total eclipse of the cluster!!! :mrgreen: :mrgreen:

I also thought I had discovered a PULSAR...but it was only ALFIE jumping up and down for his treat! :mrgreen:

This bit of kit worked fine but a cheap guidescope came up on the astro market and I thought "what the hell!". The guide camera is also a planetary camera....and a really nice one too....so for Saturn in opposition this month...that is going to be very well used in its other role.

So it all can be done on a shoestring budget...but I'm getting too old for tying laces...I prefer slip-on boots these days!! :wink:

AND...the bootfairs ain't even started yet! What fun!!! :mrgreen:

Jimi







Jim

 

[bugbear]

I actually meant to say "tracking" rather than guiding though...my fault. And I think that was what you meant too..by your reference to clocks. Autoguiding prevents cigar stars and longer trails for super long exposures where tracking errors start to take effect.

"clock drive" is a standard term (or was... )

What can now be done by guiding (computer mediated feedback from sensors) used to be done by absolute movement in the mount (engineering + constant speed motor).

BugBear

 

[Paul.J]

How about a BARN DOOR set up??

 

[jimi43]

I actually meant to say "tracking" rather than guiding though...my fault. And I think that was what you meant too..by your reference to clocks. Autoguiding prevents cigar stars and longer trails for super long exposures where tracking errors start to take effect.

"clock drive" is a standard term (or was... )

What can now be done by guiding (computer mediated feedback from sensors) used to be done by absolute movement in the mount (engineering + constant speed motor).

BugBear

Indeed it was/is...even the RA scale is in hours/mins/seconds but the autoguider on the mount I have takes the pulses from the faint star (the fainter the better)...viewed by the guide camera and corrects both RA and DEC...errors whereas a clock drive will just drive the RA with the earth's rotation by the correct amount...and sidereal and lunar rotation are a bit different too so that is taken into account in the tracking of the mount.

Basically...my aim is to make sure that the object I'm photographing doesn't move. Frankly, the easier it is for me the better and I want it to work so I can leave that bit without worrying at all....it becomes accepted. This frees up time to concentrate on the imaging itself...which is what it's all about.

I'd love to see the top of Everest for a few minutes...but I'm quite happy to go by helicopter! I am way past the "because it's there" philosophy mate! :mrgreen:

Now if we're talking woodworking..that's a different matter! :mrgreen:

Whilst I admire those who can get photos from a box Brownie..through a two inch refractor strapped to the back of a grandfather clock....I thing the new doors that are opening for amateur astronomers because of the huge leaps in technology in recent years should be embraced not snubbed by old curmudgeons who would rather be polishing their Fullerscopes! :wink:

Paul...barn doorsl...yes...that's the general principle...and all that has happened in recent years are the refinements to the original basics. Some ingenious variations have surfaced with electronics but they are really just automating that model...

I am teetering on the brink of getting a cooled dedicated CCD camera...but I want to cut my teeth on the DSLR first and learn the processing properly so I will be sticking with that for a while. I've only had three nights out with it since I bought it but this atrocious weather can't surely go on forever?! That is one thing we cannot influence no matter what gear you have... :x

Jimi

 

[bugbear]

Basically...my aim is to make sure that the object I'm photographing doesn't move. Frankly, the easier it is for me the better and I want it to work so I can leave that bit without worrying at all....it becomes accepted. This frees up time to concentrate on the imaging itself...which is what it's all about.

I'd love to see the top of Everest for a few minutes...but I'm quite happy to go by helicopter!

It all depends what interests you.

If the goal is as good an image, as easily as possible, the method is clearly to download from the hubble web site.

I'm trying to get a half decent image from VERY cheap kit, just to see if I can - it's all about problem solving, and messing around.

Your interests (and many others) lie somewhere between those two extremes.

If you hang round astro forums (I'm guessing you have...) you'll know that some people just admire the skies, either through binoculars (wide field) or dobs (very swingable, large aperture light gatherers). They regard astro photography letting a camera have scope-time that a human could have enjoyed.

None of these people are "wrong" in any sense of the word.

BugBear

 

[jimi43]

110% agree with you BB.....and the key part is that we all have our interests and we are none of us wrong.

The parallels to woodworking are very striking....the beautiful hand tool fanatics and the "devils with tails" brigade!

What irks me is that some from either camp...particularly the extremists....think that it is their life's mission to convert the rest of the world to their thinking and to totally poo poo the "opposition"! :mrgreen:

I like a foot in both camps...as you can clearly see from ancient mirror to CCD....and I listen to all...everyone has their valid points...every single one.

Since I have no intention of wanting a huge glowing gravestone/memorial...I fully intend to exploit these extremes within my budget of time and money...

Jim

 

[jimi43]

Hi Paul

Well..with one 30s shot in colour with the IR filter still in place I take it....there wasn't much more I could pull out of it so this is about all I could get out...

Very noisy but I managed to get a bit out of it.

The thing about Andromeda...is that it is so very huge. You have the core in this shot and it extends out about three times the amount each side...and possibly more we can't image.

Take a look at this shot of Andromeda....taken by my friend James Stannard and featuring in this month's (April) Sky at Night magazine:

(Click here for hi resolution image)

You can see where the part you have is only a part of the amazing beauty and enormous size of the galaxy.

Sorry I couldn't get more out of it...I will try again later as I need to play with the various settings and this is a real challenge!

Cheers

Jim

 

[Paul.J]

Thanks Jim.
Considering that my image was only a 30 second single shot its caught some detail,and you have brought some of the colours out shown in your friend fantastic image :shock:
It just amazes me that we can get such fantastic images of galaxies etc that are so far away.
Have you managed to see Panstarrs yet.We've had nothing but cloud since its been visible for us.

 

[jimi43]

Thanks Jim.
Considering that my image was only a 30 second single shot its caught some detail,and you have brought some of the colours out shown in your friend fantastic image :shock:
It just amazes me that we can get such fantastic images of galaxies etc that are so far away.
Have you managed to see Panstarrs yet.We've had nothing but cloud since its been visible for us.

Hi Paul

Indeed! That is a lot of data for only 30s....so if you choose to continue get some more and wider so you start to see the outer edges of that wonderful sight. Unfortunately for me...for most of the time...Andromeda is not visible for my setup as my house blocks most of that area of sky at the moment!

I did not see anything of even the moon...let alone the comet! Bloody sky is constantly depressingly cloudy!

Unlike the night I took this shot of Halley....

Unlike this week...in 1986 and in the Southern Hemisphere...this one was clearly visible for ages and I managed to catch this shot using a Nikon F2A...Ilford XP1 film (only newly introduced chromogenic film), on a road next to a minefield just outside Stanley in East Falklands.

I think I will not have that opportunity again as sadly the next time we see this iconic comet will be in 2061!

Jim

 

[Jensmith]

Love your friends image of the Andromeda galaxy. beautiful shot.