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Brad Schaefer talking enthusiastically about T CrB on BBC World Service “Science In Action”
https://www.bbc.co.uk/sounds/play/w3ct4sdvRobin
Spectra from 2SPOT and Tom Love now posted in the ARAS forum
http://www.spectro-aras.com/forum/viewtopic.php?p=17753A spectrum from 2024-03-12 by the 2SPOT team (amateur remote echelle spectrograph in Chile)
http://www.spectro-aras.com/forum/viewtopic.php?t=3122Very red continuum with very intense, very broad H alpha
I have released the collar. When tightened then slackened a fraction of a turn the micrometer is easier to turn.
Then I think you have found the cause of the problem. You can slacken it right off. If it turns freely then, there is no overhaul needed. I find the micrometer setting does not move on its own in normal use but if you want to be 100% sure you can always clamp the locking collar back down after you set it at the wavelength you chose. No need to lock it with the grub screw though. That is really for use in an industrial machinery where the micrometer might be used as a set stop which must stay in position under vibration etc
If the locking collar is engaged and you have the locking screw loosened, it could be worth trying to release it first. (Screw anticlockwise) I just tried mine and when the collar is engaged it can be quite tight to then disengage. Try it with your spare, engaging and disengaging the locking collar does not affect the calibration.
Re lubricant the internet suggests clock oil for micrometers. (not silicone which creeps and could end up on the optics)
If the grub screw was not loose and the locking collar cannot be turned even after loosening the screw it is unlikely that this is the reason that the micrometer had become tight. (Did it suddenly become tight or has it becoming increasingly tight over time). Can you tell from my photos and comparing with the other LHIRES if the collar is engaged or disengaged ?
Other than that I guess it needs an overhaul, removing it, unscrewing the barrel cleaning and re-lubricating. Mine is still fine after 18 years though (I recall you have a remote adjustment, could this have been preloading it causing premature wear?)
Photos with the collar engaged and disengaged
I just used a Jeweller’s screwdriver but if the grub screw is tight then it seems unlikely that the collar has moved so it probably is not the reason for the micrometer becoming tight. With mine the locking collar is close to the spectrograph body when engaged and there is a definite gap with it disengaged. I will take a couple of photos.
Cheers
RobinThere is a knurled collar at the base of the micrometer held in position with a tiny cross head grub screw which is used to lock the micrometer at a given setting. Has that got tightened down? Mine is fully wound off (anticlockwise) and locked down with the grub screw.
Cheers
RobinMeanwhile ZTF have “discovered” their second high proper motion star in the past 3 months
https://www.wis-tns.org/object/2023acmv
https://www.wis-tns.org/object/2024dumRobin
That’s odd. According to time on the confirming spectrum on TNS, it was taken a day before the discovery date
Robin
Followed this up with the GOTO team. The date of the spectrum was indeed wrong and is now corrected in TNS
Robin
That’s odd. According to time on the confirming spectrum on TNS, it was taken a day before the discovery date
Robin
Stars with H alpha emission lines (of which there are several in the Pleiades) in a narrow band H alpha filter (where the solar spectrum has a deep absorption) might be interesting.
Hi Andy,
I don’t appear to have received any newsletters since no 72 last October. Are they archived anywhere ?
Cheers
RobinInteresting. I don’t think the comparison between the mass deorbited and the amount of material in the Van Allen belt is particularly helpful as the two are not comparable (We already receive ~ 40T/day of metals from meteorites) but at the future projected rate of 23 satellite deorbits a day (in the paper) the amount of additional material would appear to be comparable.
I have just been listening to one of the scientists involved in that study on BBC world service Science in Action
https://www.bbc.co.uk/sounds/play/w3ct4sdl
starting at 22:40Robin
There could be some financial advantage to extending the time over which power can be generated rather than increasing capacity on the ground. For a region heavily dependent on solar power, the price of night time electricity must presumably attract a high premium due to the high cost of storage or alternative generating capacity.
I don’t see any convincing arguments for using LED lights with a high blue spectral content for outdoor lighting and many reasons why it should not be used. Why any council lighting engineers should still be pushing back on this these days when alternatives with a lower blue content are available is beyond me
Here is his Mario Motta’s review from a US perspective.
https://www.mariomottamd.com/street-lighting/
