Alien 13

5 minutes ago, Paul M said:

OC71 anyone?

Along with the OC35 the OC71 are my favorite transistors, even now I look out for boxed mint "mullard" versions...

I am also fond of the original ECC81 valves of the mullard variety, again very hard to get mint original examples now.

Alan

9 minutes ago, John said:

Back in 2017 the cost of ED glass was:

FPL-51 = 11x BK7

FPL-55 = 15x BK7

FPL-53 = 18x BK7

I believe the relative costs are similar today.

Given the above you would have thought that the glass used in the objective would be the principle determining factor on the overall cost of a scope

I doubt that the type of glass makes up much of the overall manufacturing cost of a scope apart from its availability.

Alan

Agreed but a well put together ST80 for example with decent focusser and premium eyepiece would be a joy to use on the right sort of targets..

Anyway God gave us small Maks, the perfect package to replace long achromatic s.

Alan

Does anyone else think that the top bit looks remarkably like "fireball XL5"?

Alan

3 minutes ago, shropshire lad said:

Thanks @wimvb for that, but surely the f stop wont affect the FOV will it, 

Very few camera lenses quote the aperture so this needs to be calculated from the f/ratio as follows A=fl/f ratio.

Alan 

Try also unscrewing the setscrew shown below, the movement can be very stiff as it engages with a kind of fluid clutch mechanism.

The screw can if over tightened protrude onto the inner ring bearing surface and also deforming it causing it to stick and grate.

Alan

9 minutes ago, shropshire lad said:

 

Canon 80D was hoping to get the FOV of both ends... 70mm and 200mm.

Thanks for that but the site is a bit confusing to me ... as it shows Telescope and eyepiece, and I have neither.

 

Just switch the view to imaging mode, most Canon cameras are listed as well as some lenses but you can just add your own info.

Alan

5 hours ago, Nigella Bryant said:

My first Newtonian was a Charles Frank 6inch on a manual eq mount. Must of been around 14 years old at the time. Saved up my summer job, Christmas and birthday money to buy it, lol. Telescope's back then in the early 70's were expensive compared to today in comparison to wages. Pic added, but not mine, this has electric drives.

I was given one of those for Christmas when I was about 13, lovely piece of kit and if I remember correctly mine came with 4 swift eyepieces..

Alan

I have not looked at the Canon R series but they look good. Would be interesting to know if the bright halos reported with the RA model are down to the optics used, camera lenses in general dont like modified cameras..

Alan

16 minutes ago, Astrofriend said:

I found a lot of USB heater on Ebay with a power control module. It's almost standard today and cheap too.

 

Lars

I use this one, works well with my lenses and will fit my Mak too.

Alan

8 minutes ago, callisto said:

Just purchased the deal....I'm learning from scratch, wish me luck 🤞

If you have used PS in the past it will be a very easy learning curve..

Alan

On 01/12/2020 at 20:11, kaiserdave said:

Hi all,

firstly i have modded my 1000d  - the lpf2 filter removal (no replacement).

I also have a uhc clip filter fitted. With this setup i am able to achieve normal focus without problem - I can achieve focus with the APT focus tool and back out before the lens hits the "stop" so no poblem there ( i think).

However when I take some test shots the stars look pretty terrible - which is particularly evident when an imaging session is stacked and the image separated into RGB mages.

The red chanel is rubbish whilst the green and blue are not bad (roughly stretched images for examples)

this was taken with the modded 1000d and a super takumar 200mm f4 lens.

 

I guess my question is what can i do to deal with this issue? 

 

Thanks! 

Adam

This is always an issue when using a modded camera with a camera lens, the best solution is to replace the removed filter with one that has a slightly wider bandwidth..

Alan

Looks great but would love to see the mount against a "standard" can of beans to get a sense of scale.. 

Alan

If the counterweight bar is threaded then add a long bolt and pack it with "penny washers"..

Alan

Hello from me, you will find answers to most question here..

Alan

OMG congrats, just noticed that Grant replied to your first post, he must have been a kid then 

Alan

11 minutes ago, Moonshed said:

Thank you for that information but unfortunately I don’t even know what a pot is if you don’t plant something in it or cook with it. I am sure though that if I do a little research it will all make perfect sense. Thanks again, I am sick of kicking the damn thing!

Keith

 

I am surprised that there is not an off the shelf solution for this as I imagine its a very common problem and not just for imagers but visual also.

There is a topic running at the moment on this..

Alan

53 minutes ago, Moonshed said:

Hi Alan, I would like to know more about those little red leds, I’ve lost count the number of times I’ve kicked the tripod legs after having got it polar aligned and star aligned. Grrrrr!

Like you I got fed up of kicking the tripod after going into the kitchen for a brew and not being able to see anything when going back out.

The solution I use is three red LEDS each wired to individual leads with heatshrink sleeve to insulate them and fitted to the mount with those little plastic adhesive clips that you use for securing phone wires. The three wires are taken to a small plastic project box that contains a 1K pot and 1K resistor in series that is wired as follows..

The resistor is connected to + of the power bank with the other end of the pot to -ve via a 5.5mm X 2.5mm socket and matching lead, the LEDs are then connected to the pot wiper and -ve end.

Alan

P.S. the three LEDs are connected in parallel. Instead off the power bank you use a couple off AA batteries with a battery holder mounted in the project box, would need to add a switch of course..

I use similar lights all run off a mobile phone power bank and a simple dimmer circuit, its a must for me as I keep running back to the kitchen during an imaging run and cant see a thing when I go back outside.

Alan

Would this be any use.

Alan

My top three.

RA camera viewfinder, used with polar scope so no bending into impossible positions and handy for having a quick look around the sky at X2 magnification on its own.

Pluto trigger for DSLR, as well as a remote intervalometer it can do the "rule of 400" automatically when using a static setup, its also great for catching lightning strikes.

USB power banks, use them to power my EQ3-2 and camera lens dew heaters oh and the little red leds around the base of my tripod (stops it being kicked in the dark).

Alan

Never had a problem myself, I shoot DSLR with lenses so if its cloudy I shoot the clouds or Moon if there is a gap, all hand held of course...

Alan

This camera sounds perfect for camera lenses especially when you get down to the short f/l Samyangs.

Alan

Astounding, never seen a better full moon..

Alan

If you are struggling to get a camera and filter wheel into the imaging train have a look at the older medium format camera lenses, they have a huge imaging circle so will be well corrected even on a full frame camera and have lots of back focus.

Alan