Ricochet

In the USA the Bresser stuff is sold under the Explore Scientific Firstlight brand (ES and Bresser are sister companies). They've got a 114mm Newtonian on an alt az mount or a 130 on an equatorial. Unfortunately the 130 on an alt az mount is showing as sold out on the ES website, but maybe now you know what it is called you might find a dealer with one in stock. With regards to the two in stock options: The 114 comes with a very lightweight mount. It might be a bit wobbly, particularly at high power. If you go with the 130/eq option be aware that with an equatorial mount there is one leg on the tripod that always has to point north and that as the mount moves the telescope it also rotates it. As the Newtonian focuser points out of the side of the telescope its position is also rotated. In order to counteract this you or your wife will need to loosen the tube rings and rotate the telescope to put the focuser in a useable position every time you change to a different target. The advantage of the equatorial mount is that once you are set up and have found a target you just have to turn one slow motion knob to keep the target centred, which your kids might find easier than the up/down and right tracking of an alt/az.

OOUK make good scopes but a Newtonian of that size on an eq mount will be a nightmare to use. That mount looks a bit bigger than an eq3 to me but even so I think that scope is probably under mounted. If it was me I would be considering if £375 is a good deal just for the OTA with a plan to build a dobsonian base for it. I would also factor in the cost of a decent 2" focuser which will require cutting a larger hole in the tube. The eyepieces will get you started but you'll soon be wanting to upgrade them.

Yes and yes. You've done some good testing there and should now be in a better position to appreciate the differences between the Hyperion and the incoming ES68 when you want to look at wider objects, or if you want to put the object off centre.

It is the same as the OVL Nirvana, which FLO sell for £85, so £50 is a good price. The reviews I've seen for the 4mm have all been good so I think it would be worth going for if you need a 4mm.

No, but I found it a bit soft and the 5mm with a 2x barlow or 8mm with a 3x barlow worked better.

You won't be able to use a binoviewer with your current scope. The focuser travel is too small and it is not strong enough to cope with the weight of a binoviewer. I would recommend increasing the magnification to cut down the brightness and increase image scale. If it is the f4.4 114mm Newt that you have I would also recommend using a barlow before the eyepiece. This will increase the focal ratio that the eyepiece "sees" and so would improve the performance of cheaper eyepieces with your scope. if you still need a filter I would probably bet something like an ND rather than a polarising filter. I found that the two closely stacked filters of a polarising filter added reflections when observing bright planets.

No, these are different things. Field curvature/flatness is where the focus position is across the entire field. In a flat field scope and eyepiece the focus position in the centre of the field is the same in the centre of the FoV as at the edge and so stars that appear as pinpoints at the centre of the FoV also appear as pinpoints at the edge. In a scope/eyepiece with field curvature the focus position at the centre of the FoV is different to at the edge of the field. Stars appearing as a pinpoint at the centre become a small disk as they drift to the edge, but when they are at the edge you can wind the focuser in or out to make them a pinpoint again. If there is a small amount of field curvature it can often be reasonably overcome by focusing on a star 1/3 of the way from centre so that the image appears reasonably flat across the whole FoV. The UFF designers have prioritised keeping the image plane flat, but this does not tell you anything about any other distortion or aberrations that may exist. From experience I know that the 24mm ES68 has a small amount of field curvature (at f6) if you look for it, but this is quite minor and enough to be a reason to ignore it. The opposite aberration to field curvature is astigmatism. This is where instead of a star being stretched into a circle by field curvature it is stretched in a manner that is not radially symmetrical. Stars can appear as lines, curves, crosses or seagulls. I do not recall this being noticeable in the ES68. By prioritising a flat field it is possible that the UFF shows some astigmatism at the edge. However, I recall that the UFF is quite a large eyepiece, I think even bigger than the ES68. This could well be the reason for that size: in order to control astigmatism whilst keeping the field flat the designer had to add more elements to the eyepiece. People who have actually used the eyepiece will have to advise on this although from the reputation of the eyepiece it will either be very minor or not noticeable. When it comes to field distortions there are two distortions. Rectilinear distortion, where straight lines become curves at the edge of the field, and angular magnification distortion, where the magnification in the centre of the field is not the same as the magnification at the edge. One of these increases in the form y = x and the other with y = tan x and so once you have an eyepiece with an apparent field over ~40° you have to have one or the other, or a mix of both. It is impossible to correct for both. If you reduce one you will increase the other. Typically minimising rectilinear distortion is preferred for terrestrial targets and minimising angular magnification distortion is preferred for astronomy. The ES68 has a small amount of RD (and so must also have AMD) and so I have kept a Meade SWA (the predecessor to the ES68) for my spotting scope instead of using a 24 Pan which has lots of RD. I have not used a UFF to know what distortion balance their designer chose but in practice I am not really bothered by either for astronomy as I tend to focus on one target at a time instead of quickly sweeping across large star fields. No, these are the best two options where the choice is "not a Panoptic".

Though a collimation cap perhaps? The smaller hole should help with centring. You could also use a Cheshire but you would need an app with manual focus else you'll just get a photo of the cross hairs.

I can see the movement of air in my 8" dob with the fan running on full speed, it looks the same as thermals from an uncooled scope. In addition, running the fan on full introduces a touch of astigmatism into the primary, so I run the fan on full power before a session and then either turn it down to the minimum speed or off completely when observing.

I don't think you can use that Clicklock. The clicklock is for fitting to 2.5" feather touch focusers which have a thread, your feather touch is a 2" with no thread. If you want to use a Clicklock I think you will have to buy the one with a 2" nosepiece and then just use the compression ring on the focuser draw tube to hold the Clicklock.

There is a 1.25" 2x ES telextender but the transmission won't be as good as the powermate and you also need to flock between the lens groups to avoid reflections.

What do you mean by "manageable"? If you're talking about weight then it is a very lightweight instrument. I can easily pick up the scope and mount with one hand if I need to move it to a different location. With regards to focus there is just about enough in focus for a 2" diagonal with most eyepieces. With the BHZ you might have to use it in 2" mode so that you gain the extra height a 2"-1.25" adaptor takes up. However, a 72mm doublet objective is so light weight that the scope is very rear heavy. With a 2" diagonal you would have to invest in a much longer dovetail and risers so that you could push the telescope so far forward that the focuser is in line with the dovetail clamp on the mount. In practice I've found that I do not use 2" accessories and instead use a 1.25" diagonal and 24 Panoptic for my wildest field. If you want to use 2" accessories you would probably be better off buying at least an 80ED to help with balance. You could add weights to the front of the scope but if you're going to increase the weight I think you might as well do that with a bigger lens and get some extra light gathering capability in return.

If the baffle tube is smooth internally there will be no issue with the flocking coming unstuck. If it has loads of microbaffles/is threaded then you might find it won't stick at all. If there is enough room inside the tube that there is no chance of diagonals, barlows etc coming into contact with the flocking then as in my photos above, I would recommend painting the flocking as well.

The Starguider is a good choice. If you want a wider field of view and are prepared to up the budget then the 10 or 13 OVL Nirvana would be a good choice. If you need to wear glasses when you are observing due to astigmatism in your eye then the 9 and 12.5 Stellalyra LER eyepieces will be a better option (assuming the effective eye relief is somewhere near the 20mm quoted).

It is due to the large exit pupil that a long focal length eyepiece creates, in this case 30mm/f6= 5mm. If you look at the exit pupil from a distance you will notice that in an obstructed scope it is a doughnut shape rather than a solid circle due to the secondary in the centre. For ease of calculation of we assume that the secondary has a diameter of 50mm then with the 30mm eyepiece the central shadow will be 1.25mm across. At night your pupil is dilated to maybe 5-7mm and the small dark centre is overwhelmed by the light coming from the outer part of the exit pupil. During the day your pupil shrinks to maybe 2mm, so having the central 1.25mm in shadow means that you begin to be able to see it. A phone camera tends to have a small aperture and hence be like a daytime pupil and so you can photograph this same effect. This effect is not specific to your 30mm eyepiece, any 30mm eyepiece will show exactly the same effect. The only way to reduce the effect is to use a smaller focal length eyepiece, which reduces the exit pupil, and hence the central shadow, to the point at which you no longer see the shadow.

I managed to get a quick test session in and the results were really good. With my delites and panoptic I couldn't see any reflections from bright objects off axis. There were some very slight issues with a couple of my SLVs but much better than before and only an issue because I was carefully looking to create them and unlikely to create a problem in practice.

I think these additions probably make these the standard recommendation for anyone looking for a £100 eyepiece.

I used a combination of flocking and the musou black paint on the inside of my 72ED. Results as follows: The dewshield has been flocked. You can see the original "Skywatcher black" in the foreground. The flocking is pretty black but there is a slight sheen at shallow angles. The inside of the focuser has been painted. The finish isn't smooth and at shallow angles it is quite reflective, although better than the original Skywatcher paint. The manufacturer recommends several really light sprayed coats for proper blackness. Painting such a large area at a very shallow angle with a brush clearly doesn't work as well. I also painted the inside of the nosepiece and extension tubes for the diagonal. They are ridged inside instead of smooth and the paintbrush can be used at a steeper angle. This has worked really well and is significantly darker than the original Baader paint. The main body of the scope has a single baffle 2/5 of the way down the tube. The baffle itself was painted and again, painting a small area worked well and the baffle is nicely blacked. After the disaster with the focuser I flocked the inside walls of the tube either side of the baffle. The musou webpage says it can be used on fabrics so after a test on a scrap piece I painted the flocking inside the tube. If you compare the flocking at the far end of the tube to the first photo you can see that the performance of the flocking at shallow angles is greatly improved. Behind the baffle it is completely dark. There was no difficulty in painting the large area of flocking, but the drying time was a lot longer than for straight onto metal and I gave the piece a full day to dry before reassembly. This is the view though the reassembled scope from the rear. The only thing not completely dark is the inside of the focuser. Based on a quick daylight test this might not be a problem but I need some clear moonlit skies to test it fully.

My guess would be that you need to tighten one of the secondary collimation screws. When you tilt the telescope in the direction that makes the laser move, it is probably the collimation screw that is on the bottom that needs tightening.

I know it is a lot of the budget but I would recommend the Stellalyra premium Cheshire if you are going to buy one. The quality and accuracy of construction is top drawer and once bought you will never need to upgrade it. I would also recommend looking into getting an adjustable observing chair. I use a drum stool with my dob, and if you go down this route look for one that spins up and down to adjust rather than one where you have to align a pin with a hole in the dark. You can also get astronomy observing chairs but one of these will probably use up your budget even on the second hand market. If you want an eyepiece then sub-£100 options are a bit more limited these days due to price rises. The 5/8/12 Starguiders or 5/7/9/12 X-Cel LXs would be good options. The APM UFF/Celestron Ultima edge should work well a bit over budget for the shorter ones and quite a bit for the longer. OVL Nirvanas are good for the money, but the range is quite limited.

Excellent news, thanks. I've ordered myself a bottle.

How is this paint holding up four months later? Have you had any issues with it flaking off?

How big of a stool and what is the resulting observing position? Are you sitting or kneeling on the ground? Sat on a second seat? Will the stool fit in an MX5 boot?

Consider carefully how you will raise the heritage to a comfortable height to observe through. Of the two I think the goto version is a better bet in this regard as it has a 3/8" thread underneath for attaching to a tripod whereas I believe the older manual design still does not have any such mounting. If you go for the manual you will have to make something. Alternatively, if it will fit in your car, FLO sell a 150p and AZ4 mount bundle for £410, which is £30 more than the price for the 200p dob (assuming you get the full price back). I think that the solid tube version would be a better telescope overall as it has a better focuser that will also allow the use of 2" eyepieces for wider field and will also be a bit easier to fit additional/different finders to up at the eyepiece end of the scope.

I've got a pair of 25s, but the width of the 12 is the same. At the widest point, which is the rubber below the top coloured band, they measure 49mm. With an IPD of 63 that will leave you 14mm between eyepieces. At the widest point of the eyecup they are 47.5mm so a gap of 15.5mm. In comparison the 18mm BCOs are 35mm in diameter which gives you a 28mm gap. My IPD is about the same (not sure of the exact measurement) and I always found the Starguiders very comfortable to use. They are not quite as good optically as the BCOs but due to the increased comfort level I often found myself using the 25s with a 3x barlow over the 18s with a 2x. Lastly some comparison photos with the BV set to an IPD of 63mm.