Mark - Coventry

3 minutes ago, Clarkey said:

The 1600 does micro lens at times but this is a smaller localised effect. The large halo around the bright star is caused by internal reflections.

There is a link here with an example of microlensing.

https://www.cloudynights.com/topic/646966-zwo-asi1600mm-pro-bright-star-issue/

Looks like two problems rather than one from the Cloudy Nights discussion. I will probably stay away from bright stars until I can afford to fix one or both of these issues! The following night I got some time on M1 with no such artefacts visible. The internal reflections have me a little stumped in fact as I have flocked all possible surfaces. I love my newtonian but maybe a refractor might prove easier to work with on bright objects.

18 hours ago, SpookyKatt said:

I think the kaleidoscope-shaped pattern you are seeing is the 1600 microlensing issue.

Kathleen

Thanks Kathleen. That is the first I have heard of 1600 microlensing. I will do some research and report back in case it helps others.

Thanks for your input. I have seen a recommendation not to image bright stars when this problem was encountered. Not really the solution which I was hoping for! It's interesting to see you have the same issue. I will keep searching and in particular look at the straightness or otherwise of the spider. I'm tempted to invest in better filters when funds allow but I prefer to solve problems without throwing money at them if at all possible...

I have been improving my Skywatcher 200 PDS in an attempt to obtain better the star shapes, generally minimise unwanted reflections and increase contrast. What I have done is:

• flock the inside of the tube
• flock the edge of the secondary mirror which is visible from the direction of the eyepiece/camera
• install a primary mirror baffle
• blacken all silvered surfaces (screw heads etc) with a Sharpie
• cut down the focusing tube by 15mm to prevent it protruding into the light path and causing odd-shaped stars

The star shapes are dramatically better than before thanks to the baffle and the cut-down focus tube. However I am getting really weird reflections which I'm struggling to track down.  I can see that the vanes look to be slightly twisted hence the split diffraction spikes and there is a very pronounced halo around the bright star Alnitak with what looks like a kaleidoscope-shaped pattern in the immediate area around the star. The halo is almost invisible in H-Alpha but really pronounced in R, G and B, especially G where you can even see the outline/shadow of the secondary mirror and spider. The kaleidoscope pattern is most visible in H-Alpha.

This is something I have not seen before making the so-called improvements! I used a ZWO 1.25" 7nm HA filter and the ZWO RGB filters optimized for ASI1600. I have read that ZWO filters are prone to halos and wondered if anyone else had experienced the same issues or, indeed, found a solution to such problems.

As an afterthought, could the odd reflections be caused by the spider not being 100% straight? it seems unlikely but I'm open to ideas.

Mark

Enjoy your Astroberry Martin! I've recently got to grips properly with it and it is an amazing piece of kit. I especially love the EKOS polar alignment assistant which is better than the one in Sharpcap IMO

Thank you Paul. You are a complete star! So easy...

I am struggling with a Kstars niggle on Astroberry. I am running 3.5.2 on both my Astroberry and my PC. On the PC whichever direction I select the horizon is presented level (or if you like the Earth's axis is plumb vertical) but on the Astroberry North and South show a level horizon whereas East and West are tilted, presumably to simulate the real angle of the Earth's axis. The issue with this is that when tilted a lot of the sky is below the horizon and therefore of no interest. The fact that the same version of Kstars behaves different in the two instances of it suggests that it is a setting which governs this but try as I might I cannot find it! Any help appreciated as Google and the Kstars manual have not given me an answer.

Thanks.

Mark

9 hours ago, Newforestgimp said:

Hi the USB hub is a RSHTECH 4 Data port & 1 Charging port on amazon £20.99 it is aluminium and 12v powered but i wouldnt call it industrial. Time will tell how long it will last but so far so good....

Thanks. The profile of the two devices is remarkably similar and they look like they sit in nice balance. And at nearly £200 less than the Powerbox Advance I am going to give this a try.

Mark

On 20/03/2021 at 09:36, Newforestgimp said:

Thank you for this suggestion, it’s arrived and it’s such a neat solution and wasn’t silly money !!!

 

Thanks for asking this question. I came on to do just the same. Would you mind telling me what the make/model usb hub is? The manufacturer's name just vanishes out of the frame...

Looks like a great topic for a beginner like me. Looking forward to it.

I've just received a second-hand finder scope with one broken cross hair. I was worried about taking it apart and fatally damaging it but this is a great solution. Thanks!

Your experience is similar to mine. I have a photo of the moon I took soon after I got my first telescope which is unremarkable compared to what can be seen on here but I find it rather special because I can still remember vividly the wonder and excitement of both seeing the view and managing to record it photographically. I first saw the Orion Nebula about a month ago and I can still feel the hairs on my neck stand up when I think about it. It was wondrous and strangely moving moment which made me feel connected to the universe. It was truly fantastic. I also showed my two grown-up children and they were blown away, never suspecting that something so unexpected and beautiful could be seen from our lowly back garden.

Thanks for the warm welcome everyone. I have decided to ditch the hair shirt already. The red dot finder of the Astromaster (Useless with a capital U) and after a frustrating evening of gyrations and lying in the frost beneath it in an attempt to get it aligned, I purchased today a Skywatcher 80ED refractor. It arrives tomorrow and I am doing my clear skies dance already in anticipation...

On 29/12/2020 at 13:55, Ags said:

Looking at getting aPi too but stuck on the silly issue of powering it. What battery pack do people usually use?

I use a Poweradd Pilot X7 20000mAh Power Bank and it runs seamlessly for 7 - 8 hours with the benefits of no mains wires etc.

On 29/12/2020 at 13:55, Ags said:

Looking at getting aPi too but stuck on the silly issue of powering it. What battery pack do people usually use?

I use a Poweradd Pilot X7 20000mAh Power Bank and it runs seamlessly for 7 - 8 hours with the benefits of no mains wires etc.

On 02/11/2020 at 15:48, Steely Stan said:

Hello all

I just ordered my first telescope, a Nexstar 8 SE (very aggressive pricing on Amazon right now), and I can already tell I walked into the stargazers meth lab!  No sooner had I placed my order than I was on ebay looking for a second hand Baader zoom.  After an hour on this forum I will probably decide I need a EQ wedge, start thinking about whether to by a powerpack or make one from a car battery.  I'll be spending £200 on petrol driving to Scotland and back to find darker skies, and....well you know the drill.  To be fair, all this is with the endorsement of my missus (that makes her a "keeper") but I now know why expensive purchases are commonly referred to as 'astronomical'.

Technically its not my first scope as my son had a tiny toy refractor which, with a lot of fiddling, gave OK views of the moon but was useless for anything dim.  Then during lockdown #1 I bought a pair of binoculars, mounted them on my camera tripod and pointed them at Jupiter and behold! - a yellow disc and four little moons in a row.  Then scoot left a bit to Saturn which revealed a little rugby ball - couldn't see the rings as such, but knew it was egg shaped for a reason....anyway, that was it - hooked.

.....and as £or astro£otography, let's not mention that to the missus.  Yet.

Stan    . .  o .     . 

 

Hi Stan,

I'm just up the road from you. I know the feeling about the cost even when the skies seem eternally cloudy! Astrophotography is the first drug I've ever taken and an expensive one at that

Mark

Hello all,

I've just joined after a few months of browsing. Having rediscovered my love of astronomy from my schooldays many years ago I'm planning to launch into astrophotography (on a budget if that is possible!) I've acquired my first GOTO mount, an Explore Scientific PMC-Eight iEXOS 100, and after a week of wrangling I think I have got my head around it. I will be using an Astroberry with Kstars/Ekos/INDI and am trying to impose some discipline on myself by sticking with my current Celestron Astromaster EQ130 reflector before getting a small refractor. I find working with what you have rather than what is perfect to be a good learning experience. Or maybe I just like wearing hair shirts...

Looking forward to being part of the community here.

Mark