Greg Shaw

I was out imaging again last night with the 135mm Samyang and thought I would look at the differences between the Astronomik filters with the Bahtinov mask. I focused using the 6nm H alpha and then swapped to the other filters to see what the focus would be like. This was all done at f2.8. I'm going to redo this target using f4 to see if it helps with the poor coma around the edges (reminds me of my newtonian without a coma corrector!) This was the focus using H alpha This was OIII This was SII Will be interesting to see if I get the same result when using f4.

I have read many blogs and posts that say its best to stop down slightly to help increase star sharpness

I wonder if its because we are using this lens with it still quite wide open and fast? I think I've read that these filters are suited up to f4. I thought that was more for vignetting issue but maybe it also causes focusing difference between the filters?

I'm currently imaging with the Astronomik 6mm S,H,O filters with my Samyang 135mm and the ASI1600MM-Cool I have in the past just used a single focus point for all the filers, this was when using them on my 150PDS I compared them by using the pegasus focus cube and the new focusing system in APT. Three was a slight difference but it was like 100 steps which is nothing for the Focus Cube. With the Samyang I am using manual focus with a small focusing jig that fits onto the lens. I was really surprised to see quite a large difference between the filters with OIII being the worst. I have the lens set to f2.8

@Droogie 2001 I'm not sure if its an option with your set up as I can't see it. But I have used the usb ports on the back of my camera to connect other devices EFW and Focuser because I have the same problem with my ASI1600MM-Cool I can't connect it to USB3 port 1 it needs to be one of the others because the camera needs a USB2 connection made first before it then swaps to USB3

@Dinglem @Richie092 Well the Nevada arrived today and I did some testing with the Pegasus. I can confirm that if you feed it 13.8v the Pegasus will still work and even show that voltage in the Pegasus control panel. I wasn't sure if the PPA would output that voltage so I asked Pegasus and they responded saying that it will output what it is input which is great news because it will mean I can still run everything from the PPA I just need to power it from the Nevada. The reason for this question about power supply to the mount was because I have been told that I should be driving the EQ6-R pro mount with 13.8v as this will help with RA guiding as it reduces the spiking by 30%. On heavier payloads it has been proven by several sources that the sweet spot is 13.6-13.8v. This is because the mounts electronics, namely the voltage regulation circuit. They are designed to handle DC battery power, which is a nominal 12v, but in fact runs from 10.8-14.4v range from a lead-acid battery. Once the voltage drops, the motors torque output is also reduced. On small payloads this isn’t an issue until about 11.2v. However, if you want flat graphs, then 13.8v is the way to go.

@Dinglem Does the mount get 13.8v doing it this way or does the PPG limit to 12v

Brilliant, I actually ordered one of these myself today. I was wondering what made you use this over powering the mount directly from the PPA? Do you also power the PPA from this or does that have its own power supply?

Hi Everyone I was wondering what are you using to power your mount? I initially used a 12v 8A mains to cigarette adaptor sold to me by RVO when I purchased the mount from them. I later swapped to the Pegasus Pocket Power Advance with their own power brick which is 12v 10a. When I look at the Pegasus control panel I can see the input was 12.4v. I have been told that I should be driving the mount with 13.8v. This annoys me bit because the Pegasus unit is not cheap and is sold as a unit to do this exact thing. So I am wondering how you are al powering your mounts from the mains as I only use my mount in the garden. Thanks Greg

Hi Baz When I did mine I tried the approach of slacking the main centre screw and adjusting each of the three screws the same number of rotations so to push the secondary further down the scope in a straight line to align with the concenter. But in the end I found this not as easy because I was using bobs knobs rather than an allen key. So I ended up slackening off the three screws and used the main centre screw to adjust the depth of the secondary. I controlled the tilt with my hand by holding the back of the secondary. Once I was happy I tightened the three screws to hold the secondary in place. Dont worry about having to adjust the three screws to line up the primary it will be very slight. You should always go back and check the secondary once you have adjusted the primary. You might have to back and forward several times, each time making smaller and smaller adjustments. This was what my secondary looked like just after the first adjustment in lining up the secondary to the focuser This is what it looked like after I had made some adjustments to the secondary to get the primary aligned, as you can see its pretty much the same. Just looking down the focus tube this is what you can see This is what it looks like when using a collimation cap This is what it looks like with a cheshire (hard to take this because the camera tries to focus on the wires in the cheshire)

Hi Baz When you are adjusting the secondary bolt have you loosened the three collimation grub screws as well? Also, something to remember once you have the perfect circle of the secondary with the concenter and remove the paper blocking the primary it is likely not to look like a circle again. This is an optical illusion and is just telling you that the primary and secondary are not lined up. This is when the three collimation grub screws on the secondary come into play.

Hi Guys I have been following this thread for a while as I bought a concenter so that I could collimate my secondary after stripping the scope down for fitting a new focuser and flocking the tube. This is what I observed and did to get a successful collimation. Hopefully this will help everyone. Before reconnecting the secondary I made sure the focuser was collimated and made the required adjustments to the focuser collimation grub screws. I then attached the secondary and made sure it was central by measuring from the centre bolt out to the side of the scope. Then I created a template out of card and clipped it to one of the spider vanes to block the primary mirror. (which isn't here but its still required to make the observing the secondary easier.) I also added a green card opposite the focuser to create a contrast from the white card. To be able to see the rings in the concenter I attached a bright light to may chair and pointed it towards the top of the tube. Because I had my focuser attached to a stepper motor I just moved the concenter out of the focuser so that I could get one of the circles close to the secondary. This is what I observed. As you can see the tilt of the secondary looks good because it's a circle, but it needs to move towards the primary some more to hit the outer ring. I achieved this by holding the back of the secondary so not to tilt the secondary and then adjusted the central bolt. Once I was happy with the position I adjusted the 3 adjustment screws to lock to hold everything in place. I have recently added bobs knobs this made it very easy because I could adjust whilst still looking through the concenter. As you can see the secondary is now a circle and one of the concenter circles goes all around the edge of the secondary. I then connected the primary to the scope and checked with a cheshire, I needed to adjust the 3 adjustment bolts slightly to apply a very small amount of tilt to get the primary all in within the secondary. I then adjusted the primary to get the donut to match the cheshire cross hairs. Once this was complete I added the two templates again and rechecked the secondary with the concenter, to make sure it was still a circle and centered under the focuser. So I learnt that the concenter is great for getting the secondary centred and round under the focuser. But still use a cheshire to apply the correct tilt to the secondary to get all of the primary in view and to adjust the primary to get the donut lined up correctly.

So I ordered a file which arrived a day early and plucked up the courage to enlarge the holes to accommodate the Moonlite adaptor plate. The file worked really well but i did catch the side of the tube so afterwards I taped up the sharp from end of the file. I was able to touch up the scratch with some acrylic paint and polished it flat to prevent the scratch from rusting. Now to flock the tube and clean the mirrors.

I've had another look and it looks like I might be able to extend the current holes rather than create new ones. In the picture you can see the mounting holes just being visible on both sides.

Hi Guys The Moonlite CR2 that I ordered a few months ago has finally arrived. It came with the 6” adaptor plate and two (0.5” & 1”) spacers. To my disappointment I discovered that the adaptor plate does not line up with the existing holes. I can only get either the top two or bottom two holes to match. I was wondering if anyone has managed to fit this focuser to a 150PDS and if you had to drill new holes? Thanks