1CM69

On 18/08/2017 at 14:32, 1CM69 said:

I know this is an old thread but I came across it when trying to find a UK supplier for 2" end caps myself.

Eventually I broadened my search and found this supplier: Vital Parts

I have just placed an order for 10 x CAP099 31.76mm or 1.25" & 5 x CAP123 50.8mm or 2" caps with VAT £18 and free 3 to 5 day shipping.

MIN order value is £15 but these caps are always handy to have, so easy to make up an order.

I'll post up images when they arrive.

The caps arrived today & I am very impressed although I did order 1" deep 1.25" caps and they sent more like 1.5" deep but better that way the the other. 

Here are some pics, first showing the 2" cap for my diagonal with nosepiece adapter and then a 1.25" cap on one of my Barlows. 

I know this is an old thread but I came across it when trying to find a UK supplier for 2" end caps myself.

Eventually I broadened my search and found this supplier: Vital Parts

I have just placed an order for 10 x CAP099 31.76mm or 1.25" & 5 x CAP123 50.8mm or 2" caps with VAT £18 and free 3 to 5 day shipping.

MIN order value is £15 but these caps are always handy to have, so easy to make up an order.

I'll post up images when they arrive.

Here is my image from a few months back, you need to zoom in quite a bit to see separation but I deliberately imaged it this way. 

More research has led me to change my mind on the 174, I've now purchased the ASI224. 

59 minutes ago, newbie alert said:

Avoid Amazon..hearing lots of scams going on..support your local telescope shop or outlet..

I thought you need the small pixel size for higher resolution..i use a 8 inch sct..works good enough on that..

OK, this has been doing my head in these last couple of days.

All the info & calculators I have found say that large pixel size is needed for long FL scopes or there is the over-sampling issue, so I spent hours trawling the net comparing cameras like for like, not that easy by the way, only to come to the realisation that over-sampling is mainly an issue with DSO imaging and star bloat.

This of course led me to be looking at the ASI174 because of the 5.86 pixels.

Now I started another thread all about this: 

but this seems like an on-going saga...

Hold the fort, looks like a possible scam on Amazon. 

Seller Pipity looks kosher but they list a lot of high value items as used but only for display purposes. 

They ask the buyer to contact them via email prior to purchase, I didn't do that, but I searched the email domain of computers4u.com and it doesn't look good. 

Lots of reports on the net. 

I have contacted Amazon to investigate. 

After much deliberation and research I finally decided against the Skyris 236 as the small pixel size wouldn't have complemented my scope. 

I then looked at the Skyris 618 but through struggling to find many reviews on the camera I started looking elsewhere, this led me to eventually purchase a ZWO ASI174MC. 

I got it through Amazon for £389 as used but just opened/unused full warranty, so great deal. 

I did consider the MM version but to be honest it's the time element for me, perhaps at some later date when I've got more time on my hands I'll go the whole mono, filter wheel etc.... 

I'm really confused as to which camera is the better one, either the 236 or 274?

Hi all,

i need a little advice please. 

I've got a CPC925 & I've decided that I'm more than likely going to be guiding it OAG using a Lodestar x2 guide camera. 

Now im thinking about upgrading my NexImage 5 & I've been looking at the Skyris 236C. 

Is the Skyris a good match for my setup?

Thanks

MoonLITE focuser just arrived & what a thing of sheer beauty. 

can't wait to try it out now, hope it works as good as it looks. 

I've just bought a Moonlite focuser from Rother Valley, fantastic deal only £244, that's without motor that I'll get at a later date but it's £50 cheaper than from Moonlite themselves & surprisingly far cheaper than my 1st port of call FLO, who only list the standard type for 2".

Really happy with the bargain and the help I received from Adam at RVO.

Hi,

I am considering going down the guiding route but have a number of questions.

I have been looking at the Celestron OAG: https://www.firstlightoptics.com/off-axis-guiders-oag/celestron-off-axis-guider-oag.html

along with the Celestron SCT OAG Adaptor: https://www.firstlightoptics.com/off-axis-guiders-oag/celestron_sct_oag_adaptor_93652.html

1. Would I still be able to use my f6.3 FR with this OAG?

I am also looking at getting a Moonlite Focuser, the FR type, which means that I could use my FR as normal infront of the focuser.

2. Would using both the Focuser & OAG be a problem?

3. Would the OAG connect to the back of the focuser or vice versa?

Thanks

15 minutes ago, SkyBound said:

Are you allowing the scope to track in all directions, as you mention  "EQ track mode north"....not sure what that means..?

The scope has 3 tracking modes; AltAz, EQ North & EQ South. 

I had it set as it should have been, EQ North

14 minutes ago, michael.h.f.wilkinson said:

As others have said, aligning on Polaris is inadequate. I have used the true NCP alignment available in my Great Polaris EQ mount, and whilst very accurate, longer exposures with FR still required guiding, I found, even at the slightly shorter focal length of the C8. Drift aligning might be able to improve the result

I think that guiding is ultimately going to be the way that I will need to go.

Just find it odd that I was getting better & longer results, still sub 30sec though, using the scope in AltAz & not on the wedge.

54 minutes ago, SkyBound said:

Hi with such a long focal length scope the PA would have to be very very good Indeed, even at f6.3 it would still need to be pretty close, lining up with Polaris is not good enough, as Polaris is not the true pole, you should be polar aligning on the NCP, which is the true pole, this will then help quite a bit., especially at your focal length.

secondly the GPS will pick up UTC (coordinated universal time)  time which is correct, the fact that your handset was an hour out does not matter, that is just a setting in the handset, you can ignore that, all it means is that the handset will display either BST or not, I don't bother altering mine which means the handset is always correct for 6 months of the year......and an hour out the other 6 months.

thirdly when balancing, do it in the Alt AZ position, first slide weights back or fourth to counter whatever you have on the back of the scope, (camera etc) then point the tube straight up and make sure it stays there, and does not fall one way or the other, you may need to add weight to the top of the tube to get balance, when you have this is fine for wedge mode (equatorial) use.

i have used an 8" Meade SCT and got subs of around 3 mins with round stars using the above method of balancing at f6.3 and about 1.5-2 mins at f10, also without the f6.3 reducer the stars will be out of shape at the edges due to field curvature, this is normal, it will be a lot better with the reducer but still not perfect.

balance is the key with fork mounted SCT scopes used on an equatorial wedge.

So my theories about counterweights or incorrect time flew out the window.

Balancing is no problem, done many times when not wedge mounted, just thought it could be an issue with the Az motor now having to lift the weights when wedge mounted instead of only rotating them through a vertical plane.

55 minutes ago, ronin said:

Any difference between the finder and the main will add to inaccuracy. Also pointing at Polaris is nice but that is not the earths rotational axis, it is about 1 degree off of the rotational axis. With a poalr scope Polaris is not in the centre it is off to one side to account for this offset.

A 9.25 has a long focal length even with a reducer, so any inaccuracies will be shown up fairly prominently. For scopes like yours I have only really seen them on a permanent pier where the pier is very accurately aligned to the earths axis. It is not the scope that is aligned in EQ mode but the pier/mount.

I did already know that Polaris is slightly off exact centre and thought that even if Polaris is located & set as bang in the middle of the crosshairs, the brain of the scope allowed for this using the set position & GPS data etc...

1 hour ago, cfpendock said:

I had a CPC on a wedge, and from what I remember, I always used the main scope rather than the finder for polar alignment.

Chris

That does sound more sensible, I'm currently reading through this: http://www.shadycrypt.com/pages/Polar/Polar.htm and it seems to lay things out in a more understandable form.

Hi all,

I was out with my scope on Saturday night and it was the first time I had setup using my Celestron Pro HD Wedge.

I followed very detailed guidance to Polar align my scope and was really blown away at how straight forward the whole procedure was and the accuracy that I had achieved straight away. The longest & most taxing part of the alignment process was initially locating and making sure that is was indeed Polaris in my finder and not another nearby star.

The scope was set to track mode EQ North & slewing from star to star was very accurate.

I attached my f6.3FR to gain a slightly wider field in order to image Pleiades in all it's glory.

I took a number of images and all except one had star trailing, even on relatively short exposures, shorter even than when I use my scope without the wedge in AltAz configuration.

Here are two images, the first is taken at ISO1600 for 5 seconds and you can see the stars are round except at the extremities which show slight trailing. The second image is again at ISO1600 but one second shorter exposure than the first, at 4 seconds and the trailing is visible, albeit slight across the whole of the image.

This was extremely frustrating, how can the second image show the starting of trailing when the exposure time is 1 second less than the first image?

I tried many other exposure/ISO settings but all showed trailing, I never got better than the result in the first image here.

I decided to start over, switching the scope off and restarting the whole Polar alignment procedure once again but this didn't help, I was getting disappointing results for very, very short exposure times.

I thought that maybe it was to do with my counterweights on my scope, it was far more trickier balancing the scope when mounted on the wedge than it is when just in AltAz configuration. Right from the get go I was concerned how the scope could possible be balanced correctly when normally in AltAz setup the counterweights are along a vertical plane but wedge mounted they could end up near to a horizontal plane.

Surely this could add to strain of the Az motor trying to rotate the scope in this format.

I assumed that maybe this was causing the trailing as the Az motor was trying to keep up with field rotation but having to lift the counterweight up on one side whilst maintaining a braking action to stop the downward action of the other counterweight directly opposite, (hard to describe, hope you get the gist).

I removed the counterweights altogether but to my embarrassment I didn't capture any images at this stage because something else crossed my mind, namely the GPS time.

I had noticed when setting up that the GPS time was off by one hour, it was still showing British Summertime & not GMT. No matter how long I left the handset hoping it would resync to the correct time it didn't & stayed this one hour ahead.

Now I hadn't experienced this before because I only got my scope in August when BST was in full swing.

Thinking that perhaps this time discrepancy could cause the trailing I was seeing I manually altered the time, once again by switching the scope off then on again to reset it & causing the need to realign.

With the scope realigned, time running out and clouds rolling in I decided to target some other stars for quick images and I seemed to get some pleasing results with much longer exposure times, although still hit and miss.

I am just trying to get to the bottom of what was going wrong here, could it really have been the hour difference in GPS time or the counterweights causing premature trailing?

I took two images of M42 at 15sec exposure, one shows the stars completely round while the other shows them as elongated and this is after manually altering the GPS time etc...

I would have thought that I could achieve exposures in the minutes at least.

What is going wrong?

As an aside I did notice that when attempting to centre an object for imaging using the right arrow button on the handset resulted in the object slowly continuing to move in that direct even after releasing the button, I had to put a couple of blips on the left arrow button to counteract this and keep the target still. Is this normal?

Any help would be great.

Kirk

I've got a pair of Helios Naturesport 10x50WA and am waiting to get Helios Apollo 15x70s